Historically, glue only refers to protein colloids prepared from animal tissues, such as hide glue, bone glue, or fish glue. The meaning has been extended to any type of glue-like substances that are used to attach one material to another.
Nearly 4,000 years ago, the Egyptians were using hide glue for their furniture adhesive. This is proven by hairs found in Pharaoh's tombs and by stone carvings depicting the process of gluing different woods. Evidence exists that the Sumerians also used glue before the Egyptians did.
Specific substances to which "glue" may refer include
Glue is also the title of a novel, see Glue (book).