from The American Heritage® Dictionary of the English Language, 4th Edition
- conj. In the event that: If I were to go, I would be late.
- conj. Granting that: If that is true, what should we do?
- conj. On the condition that: She will play the piano only if she is paid.
- conj. Although possibly; even though: It is a handsome if useless trinket.
- conj. Whether: Ask if he plans to come to the meeting.
- conj. Used to introduce an exclamatory clause, indicating a wish: If they had only come earlier!
- n. A possibility, condition, or stipulation: There will be no ifs, ands, or buts in this matter.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- conj. Supposing that, assuming that, in the circumstances that; used to introduce a condition or choice.
- conj. Supposing that; used with past subjunctive indicating that the condition is not fulfilled.
- conj. Although; used to introduce a concession.
- conj. In the event that a statement is true (a programming statement that acts in a similar manner).
- conj. Whether; used to introduce a noun clause as the object of certain verbs.
- conj. Even if; even in the circumstances that.
- n. An uncertainty, possibility, condition, doubt etc.
from the GNU version of the Collaborative International Dictionary of English
- conj. In case that; granting, allowing, or supposing that; -- introducing a condition or supposition.
- conj. Whether; -- in dependent questions.
from The Century Dictionary and Cyclopedia
- In case that; granting, allowing, or supposing that; on condition that: used in introducing a conditional sentence or clause: as, I will go if you do; if he is there, I shall see him.
- Whether: used in introducing an object clause.
- Although; notwithstanding that: as, I am honest, if I am poor; he is strong, if he is little.
Middle English, from Old English gif.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Middle English yif, yef, from Old English ġif, ġef ("if; whether, though"), from Proto-Germanic *jabai (“when, if”), from Proto-Indo-European *e-, *ē- (“then, at that time”). Cognate with Scots gif ("if, whether"), West Frisian oft ("whether"), Dutch of ("or, whether, but"), Middle Low German ef ("if, whether"), German ob ("if, whether"), Icelandic ef, if ("if"). (Wiktionary)