1530s, "gather into a heap or mass" (transitive), from Latin cumulatus "heaped, increased, augmented," past participle of cumulare "to heap," from cumulus "mound, heap" (from suffixed form of PIE root *keue- "to swell"). Related: Cumulated; cumulating; cumulant.

"to heap up," 1610s, from Latin acervatus, past participle of acervare "to heap up," from acervus "heap," which is akin to acer "sharp," from PIE root *ak- "be sharp, rise (out) to a point, pierce." Related: Acervated; acervating; acerval; acervative; acervuline "occurring in clusters; clustered" (by 1859).

"brain-sand" (anatomical), 1806, medical Latin, literally "little heap," diminutive of Latin acervus "heap," which is akin to acer "sharp" (from PIE root *ak- "be sharp, rise (out) to a point, pierce").

Old English hordere "treasurer," from hoard (n.). As "one who gathers and keeps a stock of something," c. 1500, from hoard (v.). In the negative/disapproving sense of "morbidly overzealous junk collector" by 1964.

"a heap of dung," early 14c., from dung (n.) + hill (n.).

"multi-vehicle crash," 1929, from verbal phrase pile up "to heap up" (c. 1400), which is attested from 1849 as "to accumulate," 1899 as "to wreck in a heap" (see pile (v.)).