In a conditional proposition, the part that expresses the condition by 'if' or its equivalent is called the

The part of a conditional expressing the condition with "if" is the antecedent.

A conditional has the form "if p, then q".

The "if" clause p states the condition and is the antecedent.

The "then" clause q is the consequent that follows.

The condition-stating clause is by definition the antecedent.