Scale armour may have been named after the skin of fish. It certainly looks like it.
Hundreds of small, shield-shaped plates are each riveted to a material or leather base. They are positioned like roof-tiles in staggered rows, with each scale covering the gap between two in the row above it. This creates a flexible ‘skin’ of metal plates, an excellent form of armour which can be made without the technology needed to make large pieces of iron and steel.
Scale armour had been in use since the Bronze Age, and is found playing many different protective roles. There is evidence for long scale armour coats, hoods and even horse armour.
By the time of Bannockburn, scale armour was generally used to protect the hands and/or feet, although aventails of scale were known. There is also some evidence for scale vambraces protecting the forearm.