early 15c., "to bring together" (transitive), from Latin congestus, past participle of congerere "to bring together, pile up," from com- "together" (see com-) + gerere "to carry, perform" (see gest). Medical sense of "unnatural accumulation" (1758) led to transferred (intransitive) sense of "overcrowd" (1859). Related: Congested; congesting.[congest etymology, congest origin, 英语词源]