type of jet engine, 1942, from ram (v.) + jet (n.). So called because it uses the engine's forward motion as the sole means to compress air.
Entries linking to ramjet
ram v.
c. 1300, "to beat with a heavy implement, make the ground firm by tamping," from ram (n.). By 1864 as "dash violently against, strike with great force." Related: Rammed; ramming.
jet v.1
1690s, "to sprout or spurt forth, shoot out," from French jeter "to throw, thrust," from Late Latin iectare (abstracted from deiectare, proiectare, etc.), in place of Latin iactare "to toss about," frequentative of iacere "to throw, cast," from PIE root *ye- "to throw, impel."
Middle English had a verb getten, jetten meaning "to prance, strut, swagger, be showy" (c. 1400), from getter, jetter, the Old French form of the verb. Related: Jetted; jetting.