PROTASIS

‖Prot″a‐sis (?), n. [] 1. 1. A proposition; a maxim. Johnson.
2. 2. (Gram.) The introductory or subordinate member of a sentence, generally of a conditional sentence; — opposed to apodosis. See Apodosis.
3. 3. The first part of a drama, of a poem, or the like; the introduction; opposed to epitasis. B. Jonson.