Main Entry:

es·trus

Pronunciation:

\ˈes-trəs\

Function:

noun

Etymology:

New Latin, from Latin oestrus gadfly, frenzy, from Greek oistros — more at ire

Date:

circa 1890

: a regularly recurrent state of sexual excitability during which the female of most mammals will accept the male and is capable of conceiving : heat ; also : a single occurrence of this state