Prot"a*sis (?), n. [L., fr. Gr. , fr. to stretch before, forward; before + to stretch.]
1.
A proposition; a maxim.
Johnson.
2. Gram.
The introductory or subordinate member of a sentence, generally of a conditional sentence; -- opposed to apodosis. See Apodosis.
3.
The first part of a drama, of a poem, or the like; the introduction; opposed to epitasis.
B. Jonson.
© Webster 1913.