gambeson
A padded linen jacket that acted as one of the more basic forms of armor during the medieval times. Usually worn on its own or underneath other kinds of armor such as chain or plate.
If the protective clothing has rivets in it, most likely it's a brigandine (see post #3021921 for a brigandine worn over a gambeson).
External links
The following tags are aliased to this tag: arming_doublet (learn more).