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

also : a single occurrence of this state

Examples of estrus in a Sentence

Recent Examples on the Web

Electricity is used to stimulate cell division, and, when this embryo is still just a bundle of cells on the scale of micrometres, a second dog, also in estrus, is operated on to become a surrogate mother. —Alexandra Horowitz, The New Yorker, 24 June 2024

While it’s well established that lengthening daylight triggers a cat’s estrus, the effect of rising temperatures on kitten season isn’t yet understood. —Sachi Mulkey, WIRED, 23 Mar. 2024

Normally cycling participants earned about US$335 per 5-h shift during estrus, US$260 per shift during the luteal phase, and US$185 per shift during menstruation. —Discover Magazine, 19 Nov. 2019

These results constitute the first direct economic evidence for the existence and importance of estrus in contemporary human females, in a real-world work setting. —Discover Magazine, 19 Nov. 2019

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

Kids Definition

estrus

noun

es·​trus ˈes-trəs 

1

: a periodic state during which the female of most mammals is willing to mate with the male and is capable of becoming pregnant

2

: estrous cycle

estrous

-trəs

adjective

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