noun

1. the second letter of the Greek alphabet (Β, β)
2. the second of a group or series
3. Astron. the name assigned to the second brightest star in each constellation: followed by the constellation's name in the genitive case, as Beta Geminorum
4. Comput. a version of software distributed to selected users for testing before sale
5. Finance a measure of the impact of a change in the stock market on the probable price change of a stock or stocks

Etymology: L < Gr bēta < Heb bet, lit., house; prob. of Phoen orig.

adjective