"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"). Related: Acervated; acervating; acerval; acervative; acervuline "occurring in clusters; clustered" (by 1859).