ˈbi:tə n. 1
the second
letter of the
Greek alphabet (B, Ó). 2 a second-class mark
given for a
piece of
work or in an
examination. 3 Astron. the second brightest
star in a
constellation. 4 the second
member of a
series. øbeta-blocker Pharm. a
drug that prevents the stimulation of increased
cardiac action, used to
treat angina and reduce high blood pressure. beta
particle (or ray) a fast-moving
electron emitted by
radioactive decay of substances (orig. regarded as rays). [ME f. L f. Gk]