Filly, Colt, Mare, Stallion: Horse Names by Age and Sex
A filly is a young female horse. Horse vocabulary divides animals precisely by age and sex, with a cut-off at four years.
A filly is a young female horse. Horse terminology is unusually exact, and the boundary is age four: a female under four is a *filly* and over four a *mare*, while a male under four is a *colt* and over four a *stallion* if entire or a *gelding* if castrated. Racing rules depend on these definitions. The word comes from Old Norse *fylja*, related to *foal*.
- A young female horse. *A two-year-old filly.*
- Colt — a young male. *A colt.*
- Mare — an adult female. *A brood mare.*
- Foal — a horse of either sex under one. *A newborn foal.*
- Gelding — a castrated male. *A gelding.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | filly | A fast filly. |
| Plural | fillies | Three fillies. |
| Male | colt | A colt. |
| Adult female | mare | A mare. |
| Old Norse | fylja | A filly. |
- The filly won by three lengths.Racing.
- She becomes a mare at four.The boundary.
- A foal is under one year old.Youngest.
Horse terms by age and sex
- Foal — under one year, either sex
- Yearling — between one and two
- Filly — female under four; colt — male under four
- Mare — female four and over
- Stallion — entire male four and over; gelding — castrated
Old Norse *fylja*, a young female horse, related to *foal* and to a Germanic root for young animals.
When does a filly become a mare?
Generally at four years old, though some racing authorities use five.
What is the male equivalent of a filly?
A colt. A castrated male of any age is a gelding.