Read the dictionary definition of duty. All definitions for this word.
1. work that you are obliged to perform for moral or legal reasons
1. the duties of the job
2. the social force that binds you to the courses of action demanded by that force
1. we must instill a sense of duty in our children
2. every right implies a responsibility; every opportunity, an obligation; every possession, a duty
3. a government tax on imports or exports
1. they signed a treaty to lower duties on trade between their countries