Main Entry: es·trus

Pronunciation: \ˈes-trəs\

Variant(s): or es·trum \-trəm\ or chiefly British oes·trus \ˈē-strəs\ or oes·trum \ˈē-strəm\

Function: noun

1 a : a regularly recurrent state of sexual excitability during which the female of most mammals will accept the male and is capable of conceiving : heat b : a single occurrence of this state
2 : estrous cycle