perihelion

cy-noun

perihelion m (plural perihelionau or perihelia)

perihelionau (plural)
perihelia (plural)
perihelion
berihelion (soft)
mherihelion
pherihelion

Borrowed from English perihelion, from English perihelium + -on (noun suffix), the former from Late Latin perihelium, from Ancient Greek περι- (peri-, “around, surrounding”) + ἥλῐος (hḗlĭos, “the sun”), the latter from -ον (-on, noun suffix).


nod

cy-noun

nod m (plural nodau or nodion, not mutable)

Borrowed from English node, from Latin nōdus.


Mawrth

From Middle Welsh Mawrth, from Proto-Brythonic *Mo̦rθ, borrowed from Latin mārtius. Compare Cornish Merth, Breton Meurzh.


Ganymede

Borrowed from English Ganymede, from French Ganymède, from Latin Ganymēdēs, from Ancient Greek Γανυμήδης (Ganumḗdēs).

(astronomy) Ganymede (a moon of Jupiter)


Tethys

Borrowed from English Tethys, from Ancient Greek Τηθύς (Tēthús).


Io

Borrowed from English Io, from Latin Iō, from Ancient Greek Ἰώ (Iṓ).


Rhea

Borrowed from English Rhea, from Ancient Greek Ῥέα (Rhéa).


Titan

Borrowed from English Titan, from Ancient Greek Τιτάν (Titán).


Titania

Titania
Ditania (soft)
Nhitania
Thitania


Deimos

Borrowed from English Deimos, from Ancient Greek Δεῖμος (Deîmos).


Callisto

Borrowed from English Callisto from Latin Callistō, from Ancient Greek Καλλιστώ (Kallistṓ).

(astronomy) Callisto (a moon of Jupiter)


Gwener

From Proto-Brythonic *gwener, from Latin Venus. Compare Breton Gwener, Cornish Gwener.


Dione

Borrowed from English Dione, from Latin Diōnē (“of Jupiter”), from Ancient Greek Διώνη (Diṓnē, “of Zeus”).


sêr

sêr f (collective, singulative seren, not mutable)

From Proto-Brythonic *ster, from Proto-Celtic *sterā, from Proto-Indo-European *h₂stḗr. Cognate with Cornish ster, Breton ster.

sêr tywydd

barometer earthstars, Astraeus hygrometricus

sêr y Pyreneau

Pyrenean squills, Scilla Pyrenean squill


Mimas

Borrowed from English Mimas, from Ancient Greek Μίμᾱς (Mímās).


eryr

eryrod (plural)
eryr
heryr (prothesis-h)

From Middle Welsh eryr, from Proto-Celtic *eriros (“eagle”) (compare Breton erer, Cornish er, Old Irish irar), from Proto-Indo-European *h₃érō (“large bird”).


Ewropa

Borrowed from English Europa, from Latin Eurōpa, from Ancient Greek Εὐρώπα (Eurṓpa) a Doric variant of Εὐρώπη (Eurṓpē). Doublet of Ewrop.


Iau

From Middle Welsh Ieu, from Proto-Brythonic *Yow, from Latin Iovem (accusative of Iuppiter), from Proto-Indo-European *dyew- (“sky”). Compare Breton Yaou, Cornish Yow.

accusative of <i class="Latn mention" lang="la">Iuppiter</i>


Sadwrn

From Middle Welsh Sadwrn, from Proto-Brythonic *Sadurn, borrowed from Vulgar Latin Săturnus, from Latin Sāturnus. Compare Cornish and Breton Sadorn.


arwydd

arwyddion (plural)
arwydd
harwydd (prothesis-h)

From Middle Welsh arwyð, from Proto-Celtic *ɸareweidyom; compare Old Irish airde.

arwydd y Llew

(astrology, astronomy) sign (of the zodiac)


oddf

oddfau (plural)
oddf
hoddf (prothesis-h)

From Proto-Celtic *odbos (“knot, bulge”); compare Old Irish odb.


galaeth

galaethau (plural)
galaeth
alaeth (soft)
ngalaeth

From Latin galaxiās, influenced in form by llaeth (“milk”) (compare Milky Way).


cysylltiad

cysylltiadau (plural)
cysylltiad
gysylltiad (soft)
nghysylltiad
chysylltiad

From cysylltu (“to join, connect”) + -iad.

(astrology, astronomy, grammar) conjunction


cwlwm

clymau (plural)
cylymau (plural)
cwlwm
gwlwm (soft)
nghwlwm
chwlwm

Cognate with Cornish kolm, Breton koulm, skoulm.


cyswllt

cy-noun

cyswllt m (plural cysylltau or cysylltiau)

From Middle Welsh kysswllt, from Proto-Brythonic *kusulld, from Vulgar Latin *cōnsoldus, cōnsolidus; cf. Latin cōnsolidō.

(astronomy, astrology, grammar) conjunction


prif

prifiau (plural)
prifion (plural)
prif
brif (soft)
mhrif
phrif

From Middle Welsh prif, from Proto-Brythonic *priβ̃, borrowed from Latin prīmus.


heuldro

heuldro m (plural heuldroadau, not mutable)

haul (“sun”) + tro (“turn”). Calque of English turnsole in the meaning "heliotrope".


lleugylch

lleugylchau (plural)
lleugylch
leugylch (soft)

/ˈɬeɨ̯ɡɨ̞lχ/

From lleu (“light, brightness”) + cylch (“circle”).


blwyddyn golau

cy-noun

blwyddyn golau f (plural blynyddoedd golau)

blynyddoedd golau (plural)
blwyddyn golau
flwyddyn golau (soft)
mlwyddyn golau

/ˌblʊɨ̯ðɨ̞n ˈɡɔlaɨ̯/

/ˌblʊɨ̯ðɨ̞n ˈɡɔlɛ/

/ˌblʊɨ̯ðɨ̞n ˈɡɔla/

/ˌblʊi̯ðɪn ˈɡɔlai̯/

/ˌblʊi̯ðɪn ˈɡoːlɛ/

/ˌblʊi̯ðɪn ˈɡɔlɛ/

From blwyddyn (“year”) + golau (“light”).


nawnlin

nawnlin f (plural nawnlinau or nawnliniau, not mutable)


cylchred

cylchred m or f (plural cylchredau or cylchredion)

cylchredau (plural)
cylchredion (plural)
cylchred
gylchred (soft)
nghylchred
chylchred


affelion

affelion m (plural affelionau or affelia)

affelionau (plural)
affelia (plural)
affelion
haffelion (prothesis-h)

Borrowed from English aphelion, from New Latin aphēlium, from Ancient Greek ἀπο- (apo-, “away, from, off”) + ἥλῐος (hḗlĭos, “the sun”) + -ον (-on, “noun suffix”).


tafol

tafolau (plural)
tafolion (plural)
tafol
dafol (soft)
nhafol
thafol


Haeddel Fach

Use of haeddel fach (“ploughstaff, lesser handle of a plough”).


nifwl

cy-noun

nifwl m (plural nifylau or nifylion or nifwlion, not mutable)

nifylau (plural)
nifylion (plural)
nifwlion (plural)
nifwl


Plwton

Internationalism. Borrowed from Latin Plūtō, Plūtōnem, possibly via Pluto.


Siriws

Borrowed from English Sirius from Latin Sīrius, from Ancient Greek Σείριος (Seírios).


Seren y Ci

R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “Seren y Ci”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies


Seren y Cŵn

R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “Seren y Cŵn”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies

(astronomy) Alternative form of Seren y Ci (“the Dog Star”)


cyhydedd

cyhydedd m or f (plural cyhydeddau or cyhydeddion)

cyhydeddau (plural)
cyhydeddion (plural)
cyhydedd
gyhydedd (soft)
nghyhydedd
chyhydedd


Enceladws

Borrowed from English Enceladus, from Ancient Greek Ἐγκέλαδος (Enkélados).

(astronomy) Enceladus (a moon of Saturn)


Iapetws

Borrowed from English Iapetus, from Ancient Greek Ἰαπετός (Iapetós).