in heat

Idioms  

1. In a state of sexual excitement immediately preceding ovulation. For example, Our cat's in heat so we have to keep her inside. This expression applies to most female mammals and indicates the period when the animal is fertile and most receptive to mating. [Mid-1700s]

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Example Sentences

Marcus Rashford didn't give the impression of being consumed by concerns about his future as he trained in heat that climbed above 30C in Kansas City.

From BBC • Jun. 16, 2026

"It is worrying, because it's ... very hard watching older people in heat, like suffering a lot," said Renata Stankeviciute, 43, a Lithuanian chef living in London.

From Barron's • May 26, 2026

Will it end in heat death, expanding into a frozen and lifeless expanse?

From The Wall Street Journal • May 19, 2026

Ground-level ozone, often called “smog,” is a corrosive gas that forms when pollution from vehicles and other sources reacts in heat and sunlight.

From Los Angeles Times • Apr. 22, 2026

I, meanwhile, croaked out a laugh that sounded like a rhinoceros in heat.

From "From Twinkle, with Love" by Sandhya Menon