- the second letter of the Greek alphabet (Β, β)
- the second of a group or series
- 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
- Comput. a version of software distributed to selected users for testing before sale
- Finance a measure of the impact of a change in the stock market on the probable price change of a stock or stocks
L < Gr bēta < Heb bet, lit., house; prob. of Phoen orig.
Chem. designating an organic structural position