A patch is a way of mending something that is broken by sticking a piece of something over the hole, and has given rise to the phrase "to patch something up". If you get a hole in the knee of your jeans they can be fixed by stitching a patch over the hole.
When something is made entirely of patches, it is called patchwork. Quilts are often made of patchwork.
A patch is also the name for a place you grow pumpkins or other vegetables.