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definitions

hypothesize

[hahy-poth-uh-sahyz, hi-]
verb (used without object), hy·poth·e·sized, hy·poth·e·siz·ing.
  1. to form a hypothesis.
verb (used with object), hy·poth·e·sized, hy·poth·e·siz·ing.
  1. to assume by hypothesis.
Also hypothecate; especially British, hy·poth·e·sise.

Origin of hypothesize

First recorded in 1730–40; hypothes(is) + -ize
Related formshy·poth·e·siz·er, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for hypothesises

hypothesize

hypothesise

verb
  1. to form or assume as a hypothesis
Derived Formshypothesizer or hypothesiser, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for hypothesises

hypothesize

v.

1738, from hypothesis + -ize. Related: Hypothesized; hypothesizing.

Online Etymology Dictionary, © 2010 Douglas Harper
hypothesises in Science

hypothesize

[hī-pŏth′ĭ-sīz′]
  1. To form a hypothesis.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.