from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A park or an institution in which living animals are kept and usually exhibited to the public. Also called zoological garden.
- n. Slang A place or situation marked by confusion or disorder: The bus station is a zoo on Fridays.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A park where live animals are exhibited.
- n. Any place that is wild, crowded, or chaotic.
Short for zoological garden.(American Heritage® Dictionary of the English Language, Fourth Edition)
Shortened form of zoological garden, and now the usual form. See zoology. (Wiktionary)