Meaning of IF in English

IF

I. (ˌ)if, _əf, f, chiefly dial (|)ef conjunction

Etymology: Middle English yif, if, from Old English gif; akin to Old Frisian jef, ef if, whether, Old High German ibu, oba if, whether, Gothic ibai whether, and perhaps to Latin is he, that — more at iterate

1.

a. : in the event that : in case

if the train is on time, we'll meet him

the news if false will prove distressing

b. : allowing, conceding, or granting that

if he actually did commit the crime

c. : supposing

if the money were right here on the table, you couldn't count it

d. : so long as : on condition that

if any part of the plan succeeds, you will get the credit

if you can keep your head when all about are losing theirs — Rudyard Kipling

2. : whether

not knowing if the candidate had the necessary qualifications

asked if the mail had come

doubts if two and two make four — Matthew Prior

3. — used to introduce an exclamation expressing a wish

if it would only rain

4. : even though : although perhaps

an interesting if untenable argument

if we are broke, still we got our money's worth

- if anything

II. ˈif noun

( -s )

1. : condition

an argument with too many ifs in it

: stipulation

a contract weakened by ifs

2. : supposition

a theory full of ifs

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.