positron

From positive + -tron (electron). Coined by American physicist Carl Anderson in 1932 to replace the earlier term antielectron.

coin

The notion of a positron weapon remains the stuff of science fiction.

If these particles carry unit positive charge the curvatures and ionizations produced require the mass to be less than twenty times the electron mass. These particles will be called positrons.

[1933 March 15, Carl D. Anderson, “The Positive Electron”, in Physical Review, volume 43:

(physics) The antimatter equivalent of an electron, having the same mass but a positive charge.


neutronium

From neutron + -ium. Coined by scientist Andreas von Antropoff in 1926 (before the discovery of the neutron in 1931; neutrons had been predicted to exist in 1920).

(physics) A material composed entirely of neutrons.

(physics) A hypothetical gravitationally bound system of a neutron and an antineutron (the onium of a neutron), not predicted to exist under normal circumstances.


anti-

From Ancient Greek ἀντι- (anti-, “against”). Doublet of ante-.

anti- + electron → antielectron

anti- + galaxy → antigalaxy

(particle physics) Composed of antimatter.


pion

From pi + -on, as alteration of pi-meson.

(physics) Any of three semistable mesons, having positive, negative or neutral charge, composed of up and down quarks/antiquarks.


antiparticle

There could be whole antiworlds and antipeople made out of antiparticles. However, if you meet your antiself, don't shake hands!

1988, Stephen Hawking, A Brief History of Time: From the Big Bang to Black Holes, page 75:

Particles of matter and antimatter are identical, except for an opposite electrical charge. An electron has a negative charge whereas its antiparticle, the positron, has a positive charge, and both have an identical mass.

2010 November 19, Alok Jha, “We can't see antimatter but it really does matter”, in The Guardian, →ISSN:

(physics) A subatomic particle corresponding to another particle with the same mass, spin and mean lifetime but with charge, parity, strangeness and other quantum numbers flipped in sign; a particle that has a reversed world line to another.


antimatter

en-noun

antimatter (usually uncountable, plural antimatters)

[ˈæ.ɾ̃iˌmæ.ɾɚ]

From anti- + matter. Coined by British physicist Arthur Schuster in 1898 to describe matter that resists gravity in a jocular article in Nature titled "Potential Matter.—A Holiday Dream", but not used in a modern sense until the 1940s.

coin

But most theories predict that equal amounts of matter and antimatter should have been produced during the big bang, and the mystery of what happened to all the antimatter is a central question in fundamental physics.

2023 September 27, Hannah Devlin, “Scientists find antimatter is subject to gravity”, in The Guardian, →ISSN:

(physics) Matter that is composed of the antiparticles of those that constitute normal matter.


antiproton

There were also particles no one had predicted that just appeared. Five of them […, i]n order of increasing modernity, […] are the neutrino, the pi meson, the antiproton, the quark and the Higgs boson.

2012 March-April, Jeremy Bernstein, “A Palette of Particles”, in American Scientist, volume 100, number 2, page 146:

(physics) The antiparticle of the proton, having a negative electric charge.


antineutron

(physics) The antiparticle corresponding to a neutron.

antineutroi

the antiparticle corresponding to a neutron


antineutrino

(physics) The antiparticle of the neutrino.


self-conjugate

(physics) Of a subatomic particle that is identical to its antiparticle; includes all gauge bosons except the charged W-boson and gluons.


dilithium

LL-Q1860 (eng)-Flame, not lame-dilithium.wav

(inorganic chemistry) The diatomic molecule Li₂ found in the gas phase.

(chemistry, especially in combination) Two lithium atoms in a molecule.

Fifty years later and it seems like we should—I don’t know if dilithium crystals are out there—but, you know, we should be getting some breakthroughs.

2016 October, Scott Dadich, quoting Barack Obama, “Barack Obama Talks AI, Robo Cars, and the Future of the World”, in Wired, →ISSN:

(science fiction) A fictional crystalline mineral in the Star Trek franchise, described as an essential component of anti-matter energy generation systems.


muonium

LL-Q1860 (eng)-Flame, not lame-muonium.wav

(physics, chemistry) An exotic atom formed when a positively charged muon (an anti-muon) and an electron are bound by their mutual electrical attraction; chemically equivalent to a light, short-lived isotope of hydrogen.


antihydrogen

en-noun

antihydrogen (usually uncountable, plural antihydrogens)

(physics, uncountable) The antimatter equivalent of hydrogen, consisting of an antiproton and a positron (antielectron).


antielectron

From anti- + electron. Coined by English physicist Paul Dirac in 1928 using the spelling anti-electron.


onium

LL-Q1860 (eng)-Flame, not lame-onium.wav

(chemistry) any cation derived by the addition of a proton to the hydride of any element of the nitrogen, chalcogen or halogen families


pionium

(physics, chemistry) an exotic atom equivalent to a hydrogen atom with the proton replaced by a pion


protonium

(physics) An exotic atom consisting of a proton bound to an antiproton.


quarkonium

en-noun

quarkonium (plural quarkoniums or quarkonia)

(physics) A flavorless meson whose constituents are a quark and its own antiquark.


bottomonium

bottomonium (plural bottomoniums or bottomonia)

bottomoniums (plural)
bottomonia (plural)

(physics) Any meson, such as an upsilon particle, formed from a bottom quark and its antiquark.


charmonium

charmonium (plural charmoniums or charmonia)

(physics) Any meson formed from a charm quark and its antiquark.


positronium

positronium (plural positroniums or positronia)

positroniums (plural)
positronia (plural)

(physics, chemistry) An exotic atom (specifically, an onium) consisting of a positron (anti-electron) and an electron, as a particle–anti-particle bound pair with no nucleus.


dipositronium

(physics) The short-lived combination of two positronium exotic atoms that are bound together in the same way as a hydrogen molecule


contraterrene

/ˌkɒntɹətəˈɹiːn/

This means just one thing: the instant contraterrene matter struck ordinary matter, a terrific explosion would occur!

1952, Science Digest, volume 31, page 67:

Then I started jacking up the voltage, and modified the thing with a double-polarity field somewhat similar to the molecular motion field except that it works on a sub-nucleonic level. As a result, about half of the lead fed into the chamber became contraterrene lead! The atoms just turned themselves inside out, so to speak, giving us an atom with positrons circling a negatively charged nucleus.

1957, John W. Campbell, Islands of Space:

(obsolete in physics, science fiction) Made of or pertaining to antimatter.


antiatom

(particle physics) An antiparticle composed of antiprotons, antineutrons, and positrons. An antimatter equivalent of the atom.

反原子

antimatter equivalent of atom made up of antiparticles


antibaryon

To have anti-iron we need the fundamental antifermions (positrons), the antiparticles (antimesons and antibaryons) and the property that these antiparticles must interact like the particles in order to have the antinucleus of the iron.

2001, Giovanni C. Bonsignori, Nucleus-nucleus Collisions, →ISBN:

(physics) The antiparticle corresponding to a baryon.

antibárion

the antiparticle corresponding to a baryon


antimuon

(physics) A positively charged particle, the antiparticle corresponding to a muon.


antilepton

When a W⁺ boson decays into a positron and a neutrino, lepton number is conserved because the W⁺ boson is a non-lepton, the neutrino is a lepton, and the positron is an antilepton. Likewise, when a W⁻ boson decays into an electron and an antineutrino, lepton number is conserved because the W⁻ boson is a non-lepton, the electron is a lepton, and the antineutrino is an antilepton.


toponium

From top + -onium. From top quark and "-onium" as in positronium.

(physics) Any hypothetical meson formed from a top quark and its antiquark; would be very unstable because of the large mass of the top quark


strangeonium

strangeonium (plural strangeoniums or strangeonia)

strangeoniums (plural)
strangeonia (plural)

(physics) Any meson formed from a strange quark and its antiquark


antimoon

The hypothetical analog of the Moon, revolving around the antiearth.


antideuteron

(physics) The antiparticle of the nucleus of deuterium, consisting of an antiproton and an antineutron.


antigalaxy

(astrophysics) A conjectured type of galaxy formed from antimatter.

antigaláxia

a conjectured type of galaxy formed from antimatter


antistar

(astrophysics) A conjectured type of star formed from antimatter.

αντιάστρο

a conjectured type of star formed from antimatter


antipartner

(particle physics) The antiparticle of a specific particle.


antifermion

(physics) The antiparticle of a (specified) fermion


parapositronium

(physics, attributive) The state of a positronium exotic atom in which the positron and electron have antiparallel spins


orthopositronium

(physics, attributive) The state of a positronium exotic atom in which the positron and electron have parallel spins


antitritium

(physics) The antimatter equivalent of tritium.


antideuterium

(particle physics) The antimatter equivalent of deuterium.


antihypertriton

(physics) The antiparticle equivalent of a hypertriton, consisting of an antiproton, an antineutron and any antihyperon


antihelium

antihelium (countable and uncountable, plural antiheliums)

In 1970, a more complex antinucleus, antihelium-3 (iHe), was discovered in the USSR.

1987, K. N. Mukhin, Experimental Nuclear Physics: Elementary particle physics, page 134:

In principle the energy should have been enough for the production of even heavier antinuclei. However, the probability for production of heavier masses is very tiny, and antihelium-3 is still the heaviest known antielement.

1994, Sven Kullander, Kullander Sven, Börje Larsson, Out of Sight!: From Quarks to Living Cells, →ISBN, page 218:

After several launches of their balloon, the scientists registered more than 40 million nuclei of helium in the cosmic rays, but not a single nucleon of antihelium.

2018, Borissov Guennadi, Story Of Antimatter, The: Matter's Vanished Twin, →ISBN, page 91:


antiatomic

(particle physics) Of or pertaining to antiatoms.


antiatomic

(politics, military) Opposing or countering atomic weapons.


antiquasiparticle

(physics) The antiparticle of a quasiparticle


baryonium

baryonium (plural baryoniums or baryonia)

(physics) A particle-like resonance preferentially coupled to baryon-antibaryon channels. It is described either as a baryon-antibaryon compound or composed of a diquark and an antidiquark.


pi meson

(archaic, formal) A pion, a type of meson


anticarbon

(physics, uncountable) The hypothetical antimatter equivalent of carbon.


antioxygen

antioxygen (usually uncountable, plural antioxygens)

The antimatter counterpart of oxygen. Made up of positron and antiprotons instead of electrons and protons.


antiworld

But possibly there is an antiworld in which, in addition to matter, time is also negative. […] In such an antiworld man would grow younger with time and a broken glass would come together from its fragments.

It follows that somewhere antiworlds consisting of antiparticles are bound to wander. No traces of these antiworlds have as yet been found.

1982, Rudolʹf Konstantinovich Balandin, Vladimir Vernadsky:

(astrophysics) A hypothetical world constructed from antimatter.

antimundo

a hypothetical world constructed from antimatter


antisun

antisun (countable and uncountable, plural antisuns)

(astrophysics, countable) A hypothetical sun composed of antimatter.


antiplanet

(astrophysics) A hypothetical planet composed of antimatter.

antiplaneta

a hypothetical planet composed of antimatter


antiuniverse

(astrophysics, cosmology) A conjectured universe formed from antimatter.

antiuniverso

a conjectured universe formed from antimatter


antilight

A hypothetical inverse of light, associated with antimatter.


antinitrogen

(physics) The theoretical antimatter form of nitrogen.


muononium

(physics) an exotic atom formed when an antimuon and a muon are bound by their mutual electrical attraction


tauonium

(physics) a subatomic particle formed by the bound state of a matter tauon with its antimatter partner antitauon


-onium

(particle physics) Designating an onium particle.

Alternative form: -ium

quaternary ammonium compound
quaternary ammonium compound#English

neuromuscular blocking agent
w:neuromuscular-blocking drug

(pharmacology) Used to form names of quaternary ammonium compounds used as neuromuscular blocking agents, cholinergic agents, anticholinergic agents, antibacterials/antiseptics, or other agents.


antimatter rocket

antimatter rocket (plural antimatter rockets)

A proposed form of rocket that would use antimatter as direct or indirect propellant


pbar

(physics) antiproton (pronunciation spelling of the symbol p̄)


leptonium

The LHC constraints on exotic stable massive charged particles seem to further shrink the allowed range for the hypercharge down to Y#95;#123;#92;ell#125;#92;approx 8-8.9, with the caveat that the relation between the leptonium mass and the mass of the constituent leptons in our calculations is plagued with a large theoretical uncertainty for large Y#95;#123;#92;ell#125;.

2016, Neil D. Barrie, Archil Kobakhidze, Shelley Liang, Matthew Talia, Lei Wu, “Heavy Leptonium as the Origin of the 750 GeV Diphoton Excess”, in arXiv:

(physics) A bound pair of a lepton and its antiparticle


antiperson

antiperson (plural antipersons or antipeople)

antipersons (plural)
antipeople (plural)

If a person shook hands with an antiperson, both would be annihilated in a shower of gamma ray greetings.

2002, Roy A. Gallant, Meteorite Hunter: The Search for Siberian Meteorite Craters, page 45:

A hypothetical person made out of antimatter.


antielement

He began his analysis by assuming that antimatter could be produced in adequate quantity — which he believes impossible or extremely expensive with present-day technology — and that antihydrogen would be the easiest antielement to produce.

1981, Saul J. Adelman, Benjamin Adelman, Bound for the stars, page 206:

In a neutrosophic triplet set, there is a neutral element and antielement for each element.

2018, Memet Şahin, Abdullah Kargın, Mehmet Ali Çoban, Fixed Point Theorem for Neutrosophic Triplet Partial Metric Space:

The antimatter analog of an element; antiatom.


antiearth

This principle states that, if we could somehow replace every particle on earth with its antiparticle—thus creating a sort of antiearth—no one would be able to tell the difference.

1958, Columbia University Forum - Volumes 2-3, page 29:

Each extends what would be called, on antiearth, a right hand.

1982, Martin Gardner, The Ambidextrous Universe, page 278:

But actually, CPT only tells you that if you drop an apple to the earth it will fall exactly as if you drop an antiapple to an antiearth.

1989, Ronald W. Hellings, Relativistic Gravitational Experiments in Space, page 56:

Antiapples would still fall to antiearth, radioactive antielements would still decay, and antisugar would taste sweet

1998, Meher Antia, Matter, Antimatter, and Why Are We Here:

A hypothetical analog to earth composed entirely of antimatter.


helionium

* (helion-antihelion pair): helium + -onium

Any atomic system containing a helium nucleus and an antihelium nucleus.


antihelion

The antiparticle of a helion, consisting of two antiprotons and one antineutron.


seetee

Spelling out of CT, initialism of contraterrene. Coined by American science fiction author Jack Williamson in 1942.

coined

He followed her slowly into the empty hallway, announcing flatly, “I never made a seetee weapon. I don’t intend to start now.”

1949, Jack Williamson, “Seetee Shock”, in Astounding Science-Fiction, volume 42, number 4, page 149:

He gritted his teeth as another bolt of seetee matter exploded against the energy screen.

1960, John Glasby, Black Abyss, e-book edition, published 2014, →ISBN:

She inferred what happened: the atmosphere of Yuggoth was composed of SeeTee matter. ¶ SeeTee. CT. ContraTerrene. Antimatter.

2010, Richard A. Lupoff, “Nothing Personal”, in Darrell Schweitzer, editor, Cthulhu’s Reign, →ISBN:

(science fiction) Synonym of contraterrene (“made of or pertaining to antimatter”).


positronium hydride

A molecule of the form PsH, where Ps is an exotic atom (positronium) and H is a normal atom (hydrogen)


antiprotonic helium

A form of helium where one of the electrons is replaced by an antiproton.


antilithium

Heavy antinuclei, if observed, would also indicate that nucleosynthetic processes are taking place in these antimatter regions, since the usual matter-symmetric cosmologies have no other provision for manufacturing antimatter heavier than antilithium.

1987, Luis W. Alvarez, Discovering Alvarez: Selected Works of Luis W. Alvarez with Commentary by His Students and Colleagues, University of Chicago Press, →ISBN, page 194:

The pinhead contained only a twentieth of a gramme of antilithium, but that's more than sufficient for our purposes.

2009, Alastair Reynolds, Revelation Space, Orion, →ISBN:

Even unshielded, it would take antilithium or highmatter to cut through the adamantine plate on the dorsal hull.

2020, Christopher Ruocchio, Demon In White: Book 3, Orion, →ISBN:

(physics, science fiction) The antiatom form of lithium.


anticobalt

It is believed that the same experiment with anticobalt nuclei would have the exact opposite result.

1996, Robert Ehrlich (physicist), What If You Could Unscramble an Egg?, Rutgers University Press, →ISBN, page 162:

Of course, we have not been able to test the validity of the CP conservation using anticobalt, although other experiments have been conducted to show that it is preserved to a high degree.

1991, G. D. Coughlan, J. E. Dodd, The Ideas of Particle Physics: An Introduction for Scientists, Cambridge University Press, →ISBN, page 70:

For example, in the well-known Wu experiment arguing from the observed asymmetry of Co⁶⁰-decay electrons (without the experiments on anticobalt nuclei!) it followed that charge parity was not conserved.

2013 [1965], Lev Okun, Weak Interaction in Elementary Particles: International Series of Monographs in Natural Philosophy, Elsevier Science, →ISBN, page 46: