oes·trus
noun/ˈiːstrəs/
/ˈestrəs/
(British English) (North American English estrus)
[uncountable] (specialist)- a period of time in which a female animal is fertile and ready to have sex
（雌性动物的）动情期 Word Originlate 17th cent.: from Greek oistros ‘gadfly or frenzy’.