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".

A feature of digital video systems that mimics the visual feedback given during fast forward and rewind operations that were provided by analog systems such as VCRs.

(archaic) A feat of escapism in which a person frees themselves from ropes tied around them.

(obsolete) A stratagem, a clever trick; a ruse. / A delusion; a trick of the brain. / A puzzle designed to exercise the brain.

Alternative spelling of parlour trick

Alternative form of dog trick

A spiteful or ill-natured trick played on somebody.