"pion rocket" meaning in English

{
  "etymology_text": "From the type of exhaust expelled by the rocket, being composed of π subatomic particles (π mesons, aka pions).",
  "forms": [
    {
      "form": "pion rockets",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pion rocket (plural pion rockets)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A theoretical type of antimatter rocket which uses proton-antiproton fuel, and magnetic rocket funnels to direct the π-on exhaust. The pi meson particles are created by the matter-antimatter annihilation of protons and antiprotons."
      ],
      "id": "en-pion_rocket-en-noun-omOK9lxw",
      "links": [
        [
          "antimatter rocket",
          "antimatter rocket"
        ],
        [
          "proton",
          "proton"
        ],
        [
          "antiproton",
          "antiproton"
        ],
        [
          "π-on",
          "π-on"
        ],
        [
          "pi meson",
          "pi meson"
        ]
      ]
    }
  ],
  "word": "pion rocket"
}

{
  "etymology_text": "From the type of exhaust expelled by the rocket, being composed of π subatomic particles (π mesons, aka pions).",
  "forms": [
    {
      "form": "pion rockets",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pion rocket (plural pion rockets)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns"
      ],
      "glosses": [
        "A theoretical type of antimatter rocket which uses proton-antiproton fuel, and magnetic rocket funnels to direct the π-on exhaust. The pi meson particles are created by the matter-antimatter annihilation of protons and antiprotons."
      ],
      "links": [
        [
          "antimatter rocket",
          "antimatter rocket"
        ],
        [
          "proton",
          "proton"
        ],
        [
          "antiproton",
          "antiproton"
        ],
        [
          "π-on",
          "π-on"
        ],
        [
          "pi meson",
          "pi meson"
        ]
      ]
    }
  ],
  "word": "pion rocket"
}