缎 (duàn) is a bound form meaning 'satin' – it rarely appears alone and is almost always used as part of compound words like 绸缎 (chóuduàn, 'silk satin') or 锦缎 (jǐnduàn, 'brocade'). When you see it in a sentence, expect it to be attached to another character. The free-standing noun for the fabric is 缎子 (duànzi), where 缎 is still the bound root.