The story
From canister + Damascus (“damascus steel”). From being made in a can, with the resultant steel having distinctive patterning originating from the separate steels used to make the billet.
Etymology from Wiktionary, CC BY-SA 4.0.
canister damascus
Today it means: A composite steel made by placing solid and powdered steels in a metal can, and fusing it together by forge welding using heat and pressure Full definition →