What is a "Fuller"?

[Jumbi]

and does it serve a function or is it decorative like, e.g., a blood groove?
Thanks

 

[not2sharp]

A fuller is the proper name for the blood groove. On larger knives and swords it serves the purpose of lightening the blade while retaining the structural integrity and rigidity. Think of it as an arch similar to that used on buildings.

 

[Paracelsus]

For more than you ever wanted to know about Blood grooves, Fullers, and the History, Metaphysics, and Physics of Bladesmithing, see this old thread:

Blood Groove Thread

Paracelsus