It is conventional in grammar to speak of the words which follow if (French si) as a condition for the truth of the main clause statement.
- If we don't finish tonight, we'll finish in the morning.
- I only sweep that room if I have time.
(In the second case, if is equivalent to when and similar to as long as (tant que).
In the study of language, the if-clause is called the protase (cf. French explanation)</span> of a conditional.
If is an important logical operator. In a sentence like: If A, then B.
- If A is true, B is true.
- If A is false, B can be true or false.
- provided that
- providing that
- on the condition that
- as long as
iffy (adj.) - uncertain
- Rudyard Kipling, "If—"