1778, an arbitrary formation, one of what Farmer describes as "A class of colloquialisms compounded with an intensive prefix" (ram- or rum-), probably suggesting in part rum (adj.) in its old slang sense of "good, fine," and ramp (n.2). In this case apparently suggested by boisterous, robustious, bumptious, etc. Coined about the same time were rumbustical, rambumptious "conceited, self-assertive," rumgumptious "shrewd, bold, rash," rumblegumption, rambuskious "rough," rumstrugenous. Also compare ramshackle, rambunctious.
"a deep, heavy, continuous rattling or dully roaring sound," as of thunder, late 14c., from rumble (v.). From 14c. to 17c. it also meant "confusion, disorder, tumult." The slang noun meaning "gang fight" is by 1946. The meaning "backmost part of a carriage" (typically reserved for servants or luggage) is from 1808 (earlier rumbler, 1801), probably from the effect of sitting over the wheels; hence rumble seat (1828), later transferred to automobiles.
type of Afro-Cuban dance, also a ballroom dance based on it, the rhythm of it, and the music suitable for it; 1914 ("La Rumba" was the name of a popular tango melody from 1913), from Cuban Spanish rumba, originally "spree, carousal," derived from Spanish rumbo "spree, party," earlier "ostentation, pomp, leadership," perhaps originally "the course of a ship," from rombo "rhombus," in reference to the compass, which is marked with a rhombus. The verb is recorded from 1932. Related: Rumbaed; rumbaing.
late 14c., "make a deep, heavy, continuous sound," also "move with a rolling, thundering sound," also "create disorder and confusion," probably related to Middle Dutch rommelen "to rumble," Middle High German rummeln, Old Norse rymja "to shout, roar," all of imitative origin. Slang sense of "engage in a gang-fight" is by 1959. Related: Rumbled; rumbling.