Stories We Like: A Guide to the Comma
c.1847, short for Zoological Gardens of the London Zoological Society, established 1828 in Regent's Park to house the society's collection of wild animals. From comb. form of Greek zoion "an animal," literally "a living being," from PIE root *gwei- "to live, life" (cf. Greek bios "life," Old English cwicu "living;" see bio-). Slang meaning "crowded and chaotic place" first recorded 1935.
zoo- or zo-
Animal; animal kingdom: zoonosis.
A crowded and chaotic place: Opening Day is always a zoo/ The emergency room at Bellevue was usually a zoo (1935+)