estrus
noun
es·trus ˈe-strəs 
: a regularly recurrent state of sexual receptivity during which the female of most mammals will accept the male and is capable of conceiving : heat
Some mares will exhibit estrus for 15 to 20 days.
Frederick Harper
Frederick Harper also : a single occurrence of this state
Example Sentences
Recent Examples on the Web Plus, deer kept moving in faster than they could be sterilized, which Curtis attributes to new bucks being attracted to the ongoing estrus of the does that didn’t get pregnant. Brooke Jarvis, The New Yorker, 8 Nov. 2021 As a result, the Smithsonian Conservation Biology Institute, headquartered in Front Royal, Virginia, became a leader in giant panda estrus, breeding, pregnancy, pseudopregnancy and cub development. Roger Catlin, Smithsonian Magazine, 7 Dec. 2020 Unlike female lions, which tend to become receptive to mating—also known as coming into heat, or estrus—at the same time, leopards do not. Doug Main, National Geographic, 27 June 2018 The deer was sixty yards away, moving steadily, its head down, probably following the scent of doe in estrus. New York Times, 31 Mar. 2020 Based on traces of sperm found in the days before the birth of the first joey, the researchers found that the wallabies’ estrus, or mating period, began before the pregnancy was over. Veronique Greenwood, New York Times, 2 Mar. 2020 During the peak rut, a lot of estrus does mist the woods, and bucks had lots of choices. Michael Hanback, Outdoor Life, 4 Dec. 2019 The animals are in estrus for only 24 to 72 hours each year. Michael E. Ruane, Washington Post, 27 Aug. 2019 Britain, and Wales in particular, grows lamb at a relatively natural pace, with ewes coming into estrus just once a year, to be mated with rams in the fields, to give birth in the spring, after five months gestation. Washington Post, 17 Aug. 2019 See More
Brooke Jarvis, The New Yorker, 8 Nov. 2021 As a result, the Smithsonian Conservation Biology Institute, headquartered in Front Royal, Virginia, became a leader in giant panda estrus, breeding, pregnancy, pseudopregnancy and cub development. Roger Catlin, Smithsonian Magazine, 7 Dec. 2020 Unlike female lions, which tend to become receptive to mating—also known as coming into heat, or estrus—at the same time, leopards do not. Doug Main, National Geographic, 27 June 2018 The deer was sixty yards away, moving steadily, its head down, probably following the scent of doe in estrus. New York Times, 31 Mar. 2020 Based on traces of sperm found in the days before the birth of the first joey, the researchers found that the wallabies’ estrus, or mating period, began before the pregnancy was over. Veronique Greenwood, New York Times, 2 Mar. 2020 During the peak rut, a lot of estrus does mist the woods, and bucks had lots of choices. Michael Hanback, Outdoor Life, 4 Dec. 2019 The animals are in estrus for only 24 to 72 hours each year. Michael E. Ruane, Washington Post, 27 Aug. 2019 Britain, and Wales in particular, grows lamb at a relatively natural pace, with ewes coming into estrus just once a year, to be mated with rams in the fields, to give birth in the spring, after five months gestation. Washington Post, 17 Aug. 2019 See More Word History
Etymology
New Latin, from Latin oestrus gadfly, frenzy, from Greek oistros — more at ire
First Known Use
circa 1890, in the meaning defined above
Medical Definition
estrus
noun
es·trus ˈes-trəs
variants or estrum
-trəm
or chiefly British oestrus ˈē-strəs
or oestrum ˈē-strəm
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