[ prot-uh-sis ]
/ ˈprɒt ə sɪs /

noun, plural prot·a·ses [prot-uh-seez] /ˈprɒt əˌsiz/.

the clause expressing the condition in a conditional sentence, in English usually beginning with if.Compare apodosis.
the first part of an ancient drama, in which the characters are introduced and the subject is proposed.Compare catastasis, catastrophe(def 4), epitasis.
(in Aristotelian logic) a proposition, especially one used as a premise in a syllogism.

Origin of protasis

1610–20; < Late Latin: introduction in a drama < Greek prótasis proposition, literally, a stretching forward, equivalent to pro- pro-2 + tásis a stretching (ta-, verbid stem of teínein to stretch + -sis -sis) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for protasis

British Dictionary definitions for protasis

/ (ˈprɒtəsɪs) /

noun plural -ses (-siːz)

logic grammar the antecedent of a conditional statement, such as it rains in if it rains the game will be cancelledCompare apodosis
(in classical drama) the introductory part of a play

Derived forms of protasis

protatic (prɒˈtætɪk), adjective

Word Origin for protasis

C17: via Latin from Greek: a proposal, from pro- before + teinein to extend
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