1957, acronym for random access memory (computerese).
Old English ramm "male sheep," also "battering ram, instrument for crushing or driving by impact," and the zodiac sign; earlier rom "male sheep," a West Germanic word (cognates: Middle Low German, Middle Dutch, Dutch, Old High German ram), of unknown origin. Perhaps [Klein] connected with Old Norse rammr "strong," Old Church Slavonic ramenu "impetuous, violent."
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.