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[if] /ɪf/
in case that; granting or supposing that; on condition that:
Sing if you want to. Stay indoors if it rains. I'll go if you do.
even though:
an enthusiastic if small audience.
He asked if I knew Spanish.
(used to introduce an exclamatory phrase):
If only Dad could see me now!
when or whenever:
If it was raining, we had to play inside.
a supposition; uncertain possibility:
The future is full of ifs.
a condition, requirement, or stipulation:
There are too many ifs in his agreement.
ifs, ands, or buts, reservations, restrictions, or excuses:
I want that job finished today, and no ifs, ands, or buts.
Origin of if
before 900; Middle English, variant of yif, Old English gif, gef; akin to Old Norse ef if, Gothic ibai whether, Old High German iba condition, stipulation
1, 2. If, provided, providing imply a condition on which something depends. If is general. It may be used to indicate suppositions or hypothetical conditions (often involving doubt or uncertainty): If you like, we can go straight home. If I had known, I wouldn't have gone. If may mean even though: If I am wrong, you are not right. It may mean whenever: If I do not understand, I ask questions. Provided always indicates some stipulation: I will subscribe ten dollars provided (on the condition ) that you do, too. Provided he goes, we can go along. Providing means the same as provided, that is, just in case some certain thing should happen: We will buy the house, providing (provided ) we can get a mortgage.
Usage note
If meaning “whether,” as in I haven't decided if I'll go, is sometimes criticized, but the usage has been established in standard English for a long time.

if Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for if


conjunction (subordinating)
in case that, or on condition that: if you try hard it might work, if he were poor, would you marry him?
used to introduce an indirect question. In this sense, if approaches the meaning of whether
even though: an attractive if awkward girl
  1. used to introduce expressions of desire, with only: if I had only known
  2. used to introduce exclamations of surprise, dismay, etc: if this doesn't top everything!
as if, as it would be if; as though: he treats me as if I were junior to him
an uncertainty or doubt: the big if is whether our plan will work at all
a condition or stipulation: I won't have any ifs or buts
Word Origin
Old English gif; related to Old Saxon ef if, Old High German iba whether, if


intermediate frequency
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Contemporary definitions for if's 21st Century Lexicon
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Word Origin and History for if

Old English gif (initial g- in Old English pronounced with a sound close to Modern English -y-), from Proto-Germanic *ja-ba (cf. Old Saxon, Old Norse ef, Old Frisian gef, Old High German ibu, German ob, Dutch of "if, whether"), from PIE pronomial stem *i- [Watkins]; Klein, OED suggest probably originally from an oblique case of a noun meaning "doubt" (cf. Old High German iba "condition, stipulation, doubt," Old Norse if "doubt, hesitation," Swedish jäf "exception, challenge"). As a noun from 1510s.

Online Etymology Dictionary, © 2010 Douglas Harper
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if in Medicine

IF abbr.
initiation factor

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Related Abbreviations for if


  1. infertility
  2. interferon
  3. intermediate frequency
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Idioms and Phrases with if
The American Heritage® Idioms Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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