Definition of "horse"
horse1
/hɔːs/
noun
countable and uncountable, plural horses
(US) An informal variant of basketball in which players match shots made by their opponent(s), each miss adding a letter to the word "horse", with 5 misses spelling the whole word and eliminating a player, until only the winner is left. Also HORSE, H-O-R-S-E or H.O.R.S.E. (see H-O-R-S-E on Wikipedia.Wikipedia ).
(dated, slang, among students) A translation or other illegitimate aid in study or examination.
(dated, slang, among students) Horseplay; tomfoolery.
horse2
/hɔːs/
verb
third-person singular simple present horses, present participle horsing, simple past and past participle horsed
(transitive) To play mischievous pranks on.
(transitive, dated) To urge at work tyrannically.