An Etymological Dictionary of Astronomy and Astrophysics

1. A stream of a liquid, gas, or small solid particles forcefully shooting forth from a nozzle, orifice, etc.
   
2. Fountain-like formations of gas and/or dust gushing out from compact regions of some astronomical objects. → astrophysical jets.
   
3. Meteo.: A common abbreviation for → jet stream.
   
4. Shortened of → jet plane.

Etymology (EN): Jet, from M.Fr. jeter “to throw,” from V.L. *jectare, alter. of L. jactare, from jac- “throw” + -t- frequentative suffix + -are infinitive suffix; PIE base *ye- “to do” (cf. Gk. hienai “to send, throw;” Hittite ijami “I make”).

Etymology (PE): Ešân, from ešândan, → eject; šân contraction of ešân.