(US, around New York City, Connecticut, Rhode Island) A particular night, commonly the night of the 30th to the 31st of October, during which young people play pranks and do mischief in their neighborhoods.

A method of cheating somebody by winning their confidence and inducing them to hand over money (or other valuables).

plural of trick play

(American football) A play in American football that uses deception and unorthodox strategies to fool the opposing team. / (uncountable) Synonym of trick mode

A plot device in traditional literature and theatre where a character begins sexual activity with someone else, then steals away after the lights are off, allowing another character to continue instead.

Third-person singular simple present indicative form of trick-or-treat

simple past tense and past participle of trick-or-treat

(set theory) A method for giving a definition of equivalence classes for equivalence relations on a proper class, relying on the axiom of regularity but not on the axiom of choice.

Any magic trick involving playing cards.

(mathematics) A method for proving Gödel's incompleteness theorems without the assumption that the theory being considered is ω-consistent. While Gödel's original proof uses a sentence that states (informally) "This sentence is not provable", Rosser's trick uses a formula that says "If this sentence is provable, there is a shorter proof of its negation".