stud

1. A male animal, especially a stud horse (stallion), kept for breeding.
2. A female animal, especially a studmare (broodmare), kept for breeding.
3. A group of broodmares or other animals kept for breeding.
4. A group of locomotives
5. An animal (usually livestock) that has been registered and is retained for breeding. · at stud
6. A place, such as a ranch, where such animals are kept.
7. A sexually attractive, promiscuous male. (colloquial)
8. A sexually dominant lesbian, chiefly African-American. (slang)

Plural studs