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estrus

American  
[es-truhs] / ˈɛs trəs /
Rarely estrum

noun

Zoology.
  1. the period of heat or rut; the period of maximum sexual receptivity of a female mammal.

  2. estrous cycle.


estrus British  
/ ˈɛstrəs, ˈiːstrəs /

noun

  1. the usual US spelling of oestrus

"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

estrus Scientific  
/ ĕstrəs /
  1. A regularly recurring period in female mammals other than humans during which the animal is sexually receptive. Estrus occurs around the time of ovulation.

  2. Also called heat


Other Word Forms

Etymology

Origin of estrus

First recorded in 1885–90; from Latin oestrus oestrus

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

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.

From Salon Mar. 19, 2024

Otter moms will often go immediately into estrus if they lose a pup.

From Los Angeles Times Jul. 12, 2023

In female sheep, the estrus cycle is coordinated by the length of the day and does not begin until day length shortens.

From Textbooks Jun. 9, 2022

“We thought, maybe the swamp wallaby is pushing estrus back into pregnancy so it has a longer period of receptivity to find a male in the wild.”

From New York Times Mar. 2, 2020

Even mainstream trainers would drop pennies in mares’ water buckets to halt estrus, or exhaust themselves trying to get a mane that fell to the left—a bad omen—to fall to the right.

From "Seabiscuit: An American Legend" by Laura Hillenbrand

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