[ es-truh s ]
/ ˈɛs trəs /

noun Zoology.

Also es·trum [es-truh m] /ˈɛs trəm/, oestrus. the period of heat or rut; the period of maximum sexual receptivity of the female.

Origin of estrus

1885–90; < Latin oestrus oestrus

Related forms

es·tru·al [es-troo-uh l] /ˈɛs tru əl/, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for estrual


/ (ˈɛstrəs, ˈiːstrəs) /


the usual US spelling of oestrus

Derived Forms

estrous, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for estrual



The periodic state of sexual excitement in the female of most mammals, excluding humans, that immediately precedes ovulation and during which the female is most receptive to mating; heat.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for estrual


[ ĕstrəs ]

A regularly recurring period in female mammals other than humans during which the animal is sexually receptive. Estrus occurs around the time of ovulation. Also called heat

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.