pony

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A horse of any of several stocky breeds that are small in size when full grown, such as the Shetland pony.
• noun Informal A racehorse.
• noun Sports A polo horse.
• noun Something small for its kind, especially a small glass for beer or liqueur.
• noun A word-for-word translation of a foreign language text, especially one used as an aid in studying or test-taking.
• noun Chiefly British The sum of 25 pounds.
• transitive verb To lead (a horse) with another horse.

from The Century Dictionary.

• To use a pony in translating: as, to pony a piece of Latin.
• noun Something very small of its kind: an attributive use.
• To pay; settle; put: with up.
• noun A very small horse; specifically, a horse less than 13 hands in height.
• noun The sum of £25.
• noun A translation of a Greek or Latin author used unfairly in the preparation of lessons; hence, any book so used: same as horse, 9. [School and college slang.]
• noun A very small drinking-glass.
• noun The quantity (of liquor) contained in such a glass.
• noun A small raft of logs.
• noun In the West Indies, a small tree, Tecoma serratifolia.

from the GNU version of the Collaborative International Dictionary of English.

• noun A small horse.
• noun Slang, Eng. Twenty-five pounds sterling.
• noun College Cant A translation or a key used to avoid study in getting lessons; a crib; a trot.
• noun Slang A small glass of beer.
• noun a light, low chaise, drawn by a pony or a pair of ponies.
• noun [U.S.] a small locomotive for switching cars from one track to another.
• noun (Locomotive Engine) a truck which has only two wheels.
• noun (Bridge Building) a truss which has so little height that overhead bracing can not be used.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Cockney rhyming slang Of little worth.
• noun Any of several small breeds of horse under 14.2 hands.
• noun regional A small serving of an alcoholic beverage.
• noun Australia, New South Wales, Victoria A serving of 140 millilitres of beer.
• noun UK, slang Twenty-five pounds sterling.
• noun US, slang A translation used as a study aid; loosely, a crib, a cheat-sheet.
• noun Cockney rhyming slang (from "pony and trap") Crap; rubbish, nonsense.
• verb transitive To lead (a horse) from another horse.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a range horse of the western United States
• noun an informal term for a racehorse
• noun a small glass adequate to hold a single swallow of whiskey
• noun any of various breeds of small gentle horses usually less than five feet high at the shoulder
• noun a literal translation used in studying a foreign language (often used illicitly)