Definition of if :
1. In case that; granting, allowing, or supposing that; - introducing a condition or supposition.
2. Whether; - in dependent questions.
on the assumption that,
on the occasion that,
with the condition that
I were sure I could help you. - "The Squire's Daughter",
Silas K(itto) Hocking.
it have, it is my kinsman's. - "I and My Chimney",
Let us see if
that is so. - "Home Scenes, and Home Influence A Series of Tales and Sketches",
T. S. Arthur.