conjunction

1. on condition that; in case; supposing if I come, I'll see him; if I were you, I wouldn't do that
2. allowing that; granting that if she was there, I didn't see her
3. whether: used to introduce an indirect question ask him if he knows her

Etymology: ME < OE gif, akin to Ger ob (OHG oba, ibu, Goth ibai): ult. source uncert.

noun

1. a supposition or speculation
2. a condition or qualification a clause filled with ifs

1. Baseball infield
2. intermediate frequency