protasis

From Late Latin protasis, from Ancient Greek πρότασις (prótasis), from προτείνω (proteínō, “put forward, tender, propose”), from πρό (pró) + τείνω (teínō, “stretch”).

protasis (plural protases)

The first part of a play, in which the setting and characters are introduced.
- 1922, James Joyce, Ulysses:
  It doubles itself in the middle of his life, reflects itself in another, repeats itself, protasis, epitasis, catastasis, catastrophe.
(logic, grammar) A clause that expresses a contingent element in a conditional sentence.
Synonyms: antecedent, conditional, hypothesis, implicans

Coordinate terms: apodosis, implicate, implicand

In "I will be coming if this weather holds up", "if this weather holds up" is the protasis, and "I will be coming" is the apodosis.
- 2005 B. P. Bairan: An Introduction to Syllogistic Logic
  Every conditional statement is made up of two component statements. The component statement that follows the "if" is called antecedent (or the "implicans" or — rarely — the "protasis"), and the component statement that follows the "then" is the "consequent"(or the "implicate" or — rarely — the "apodosis").

clause that expresses a contingent element in a conditional sentence

English