oestrus

 
Pronunciation: /ˈiːstrəs, ˈɛstrəs/
(US estrus)

noun

[mass noun]
  • a recurring period of sexual receptivity and fertility in many female mammals; heat: a mare in oestrus

Derivatives

oestrous

adjective

Origin:

late 17th century: from Greek oistros 'gadfly or frenzy'