“gathered into a ball or rounded mass,” 1570s, from Latin conglomeratus, past participle of conglomerare “to roll together, concentrate, heap up,” from assimilated form of com “with, together” (see con-) + glomerare “to gather into a ball, collect,” from glomus (genitive glomeris) “a ball, ball-shaped mass,” possibly from PIE *glem- (see glebe).