if Meaning, Definition & Usage

If conjunction
Etymology
OE. if, gif, AS. gif; akin to OFries. ief, gef, ef, OS. ef, of, D. of, or, whether, if, G. ob whether, if, OHG. oba, ibu, Icel. ef, Goth. iba, ibai, an interrogative particle; properly a case form of a noun meaning, doubt (cf. OHG. iba doubt, condition, Icel. if, ef, ifi, efi), and therefore orig. meaning, on condition that.
Definitions
  1. In case that; granting, allowing, or supposing that; -- introducing a condition or supposition.
    Tisiphone, that oft hast heard my prayer, Assist, if OEdipus deserve thy care. Pope.
    If thou be the Son of God, command that these stones be made bread. Matt. iv. 3.
  2. Whether; -- in dependent questions.
    Uncertain if by augury or chance. Dryden.
    She doubts if two and two make four. Prior.

Webster 1913