What do we call the protective metal clothing worn by knights?

The story behind the answer

The question asks for the collective term for a knight’s protective metal clothing, and only one option names the entire suit. A helmet protects just the head, a shield is handheld defense, and a surcoat is a cloth garment worn over the metal layers, often displaying heraldry. The full defensive kit included mail (interlinked rings), later reinforced or replaced by plate components like breastplates, gauntlets, and greaves.

Protection evolved from flexible chain mail in the 12th–13th centuries to articulated plate by the 14th–15th. A complete suit typically weighed 20–30 kg, distributed across the body so a trained fighter could run, mount a horse, and fight effectively—more like carrying a hiking backpack than wearing a statue.