a range horse of the western United States
"The cowboy guided his pony across the vast plains of Montana."
a small glass adequate to hold a single swallow of whiskey
"After polishing his silverware, he poured a generous amount into the pony before taking a swift sip."
any of various breeds of small gentle horses usually less than five feet high at the shoulder
"The farmer rode his pony across the field to deliver the fresh milk."
A small horse; specifically, any of several small breeds of horse under 14.2 hands at the withers.
"Stop telling me that story and give me some straight answers instead of all your pony."
Crap; rubbish, nonsense.
In plain English: A pony is a small horse that stands shorter than four feet at its tallest point.
"The child rode her pony around the park every afternoon after school."
Usage: Use this word to refer to a young or small adult horse that stands less than fourteen and two-hands high, rather than using it for miniature horses which are distinct breeds. When used as a verb in equestrian contexts, it specifically means leading one horse by the bridle while riding another.
To lead (a horse) from another horse.
"The experienced rider was asked to pony her new mount across the river while it learned to swim."
In plain English: To pony up means to quickly pay your share of money when it is needed right away.
"The children ran to the river and decided to pony up their allowance for ice cream."
Of little worth.
"The dealer offered to sell me the antique clock, but I knew it was a total pony and wouldn't fetch much at auction."
An athletic shoe or other piece of athletic gear of an American-based brand of that name.
"I bought a new pair of Puma sneakers, but my friend thinks they look like tiny ponies because of the logo on the side."
1659 from Scots powny, apparently from Middle French poulenet ("little foal"), ultimately from Late Latin pullanus ("young of an animal"), from pullus (cognate to English foal). Sense "small serving of alcohol" from 19th century, both for small sizes generally and for a quarter pint specifically, from the small size.