A yearling is a racehorse or a deer that is one year old.
The horse sold for $20,000 as a yearling.
yearling in British English
(ˈjɪəlɪŋ)
noun
1.
the young of any of various animals, including the antelope and buffalo, between one and two years of age
2.
a thoroughbred racehorse counted for racing purposes as being one year old until the second Jan 1 following its birth
3.
a.
a bond that is intended to mature after one year
b.
(as modifier)
yearling bonds
adjective
4.
being a year old
yearling in American English
(ˈjɪrlɪŋ)
noun
1.
an animal one year old or in its second year
2. Horse Racing
a horse one year old: all thoroughbreds' birthdays are arbitrarily set at January 1, at which time a foal born on any date of the preceding year is reckoned one year old