Texture is the physical feel of something — smooth, rough, fuzzy, slimy, and lots of textures something in between.
Sandpaper is very rough — it has a gritty, rough texture. Other things, like linoleum, have a smooth texture. Texture has to do with how an object feels and it's ingredients. Texture is very important in clothes: a cotton shirt has a different texture than a polyester shirt. You can also talk about other kinds of texture, like musical texture. A symphony and a rock song have different instruments, so they have different textures.