Paste is like glue. If you paste something, you stick it onto something else. You might copy and paste info from one document to another on your computer, or literally paste posters all over town. Just don’t use tomato paste.
Some foods take the form of a paste, like cake frosting or pâté. There's also the kind of paste you can use for gluing paper — like wallpaper paste, for example. Costume jewelry, which resembles gemstones but is relatively inexpensive, is made from another, harder kind of paste. To paste something is to stick it together, to patch it, or to cover it with paper. The Late Latin root is pasta, or "dough."