used to introduce a condition on which something depends
If it rains tomorrow, we will cancel the picnic.
You can have dessert if you finish your vegetables.
✦ Old English gif, gief ‘if, whether’, of Germanic origin.
used to introduce an indirect question meaning ‘whether’
I’m not sure if he will join us for dinner.
Do you know if the train has already left?
✦ Same origin as the conditional ‘if’; over time, it also came to replace ‘whether’ in many contexts.
a condition or doubt that could affect what happens
The plan sounds good, but there is one big if—the budget.
Success depends on several ifs and variables.
✦ Developed from the conjunction, first recorded as a noun in the 16th century to mean ‘condition or stipulation’.
