If you supply someone with something that they want or need, you give them a quantity of it.

You can use supplies to refer to food, equipment, and other essential things that people need, especially when these are provided in large quantities.

A supply of something is an amount of it which someone has or which is available for them to use.

Supply is the quantity of goods and services that can be made available for people to buy.

If you supply a missing word or piece of information, for example in a puzzle, you say or write it because you know it.

If something is in short supply, there is very little of it available and it is difficult to find or obtain.