Why is a brothel called a cathouse?

Prostitutes have been called cats since the fifteenth century, for the simple reason that the urban female cat attracts many toms when she is on heat and mates with them one after the other. As early as 1401, men were warned of the risks of chasing the 'cattis tailis', or cat's tail.

This also explains why the word 'tail' is sometimes used today as slang for female genitals. A similar use for the word 'pussy' dates from the seventeenth century.