protasis
noun
°the first part of a play, in which the setting and characters are introduced.
"1922: It doubles itself in the middle of his life, reflects itself in another, repeats itself, protasis, epitasis, catastasis, catastrophe. — James Joyce, Ulysses"
°the antecedent in a conditional sentence.
"example: In, "I will be coming if this weather holds up", "this weather holds up" is the protasis"
synonyms: antecedent, conditional, hypothesis