What is the meaning of If?

Supposing that, assuming that, in the circumstances that; used to introduce a condition that may be (or prove to be) either true or false.

A keyword that invokes conditional processing: in the event that a given condition is true, execute the given statement(s) (otherwise execute other statements).

Supposing that; used with past or past perfect subjunctive to indicate a counterfactual or hypothetical condition.

Even if; even in the circumstances that.

Considering the fact that; given that; introducing a condition that is known to be true.

When; whenever; every time that.

Although; used to introduce a concession.

Whether; used to introduce a noun clause, an indirect question, that functions as the direct object of certain verbs.

Introducing a relevance conditional.

An uncertainty, possibility, condition, doubt etc.

yew

"what-if" alternative history / events

if, on condition that

yew

yew wood

Alternative form of yith

yew

if

Source: wiktionary.org