if

/ɪf/ conjunction (IN THAT SITUATION)

Definition

› used to say that a particular thing can or will happen when, only when, or after something else happens or becomes true: We’ll have the party in the backyard if the weather’s good. If anyone calls for me, just say I’ll be back at 4 o’clock. Would you mind if I opened the window (= May I open it)? › If is also used to talk about the amount or degree of something: This time of year we get little, if any, rain (= almost none). › If can mean when: If I don’t have a cup of coffee in the morning, I’m useless. › If can also mean in case it is true that: I’m sorry if I’ve offended you. if it weren't for › When you say if it weren't for or (also if it hadn't been for)something, you mean if it were not true or had not happened, the situation would be different: If it weren’t for your help, we would never have finished in time.

(Definition of if conjunction (IN THAT SITUATION) from the Cambridge Academic Content Dictionary © Cambridge University Press)