What is Bear Spread?

Legal Definition
In options trading, a bear spread is a bearish, vertical spread options strategy that can be used when the options trader is moderately bearish on the underlying security.

Because of put-call parity, a bear spread can be constructed using either put options or call options. If constructed using calls, it is a bear call spread. If constructed using puts, it is a bear put spread.
-- Wikipedia
Legal Definition
An OPTION strategy that attempts to take advantage of a BEAR MARKET; spreads can be structured as bearish CALL SPREADS (purchase of a CALL OPTION and sale of a second call, where the short call is struck closertothemoney) or bearish PUT SPREADS (purchase of a PUT OPTION and sale of a second put, where the long put is struck closertothemoney). Also known as MONEY SPREAD, PRICE SPREAD, VERTICAL SPREAD. See also BULL SPREAD.