From DT Online
The term 'Dowel' most commonly refers to circular rods of timber. Wooden Dowel (or Dowelling) is available in a range of sizes - 5mm, 6mm, 8mm 10mm and 12mm being in common use.
Features and Applications
Dowel rods can be cut into short lengths and used to reinforce Butt Joints. When used to make a Dowel Joint in this way, it is important to create a 'flat' along the length, or make a saw cut, to allow the excess glue to escape when the joint is brought together under pressure. Commercially available pre-cut Dowels are ribbed along their length for the same purpose.
Short lengths of Dowel can also be made by driving pieces of timber through a Dowel Plate.