A condition is a supposition on which a statement is based. A conditional sentence commonly consists of two clauses:
The protasis: the conditional, or subordinate, clause, expressing a supposed or assumed case (if).
The apodosis: the conclusion, or principal clause, expressing what follows if the condition is realized. The truth or fulfilment of the conclusion depends on the truth or fulfilment of the conditional clause.
a. The protasis has its name from πρότασις, lit. stretching forward, that which is put forward (in logic, a premiss); the apodosis, from ἀπόδοσις, lit. giving back, return; i.e. the resuming or answering clause.