双重 (shuāng chóng) is an adjective meaning 'double, dual' — it describes something that has two aspects, purposes, or roles (e.g., a dual purpose). It differs from 兼 (jiān), which is a verb meaning to hold two positions concurrently; 双重 is a property, while 兼 is an action. 双边 (shuāng biān) means 'bilateral' (between two sides), a narrower sense.