Occam's razor (n.)

when two competing hypotheses explain the data equally well, choose the simpler. Or, as Sir William Hamilton puts it, "Neither more, nor more onerous, causes are to be assumed, than are necessary to account for the phenomena." Named for English philosopher William of Ockham or Occam (c. 1285-c. 1349), "The Invincible Doctor," who expressed it with Entia non sunt multiplicanda praeter neccssitatem.

So called after William of Occam (died about 1349): but, as a historical fact, Occam does not make much use of this principle, which belongs rather to the contemporary nominalist William Durand de St. Pourçain (died 1332). [Century Dictionary]

updated on July 29, 2019

Definitions of Occam's razor from WordNet

Occam's Razor (n.)
the principle that entities should not be multiplied needlessly; the simplest of two competing theories is to be preferred;
Synonyms: Ockham's Razor / principle of parsimony / law of parsimony
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