A patch on a surface is a part of it which is different in appearance from the area around it.

A patch of land is a small area of land where a particular plant or crop grows.

A patch is a piece of material which you use to cover a hole in something.

A patch is a small piece of material which you wear to cover an injured eye.

If you patch something that has a hole in it, you mend it by fastening a patch over the hole.

A patch is a piece of computer program code written as a temporary solution for dealing with a virus in computer software and distributed by the makers of the original program.

If you have or go through a bad patch or a rough patch, you have a lot of problems for a time.

If you say that someone or something is not a patch on another person or thing, you mean that they are not as good as that person or thing.