Longman Dictionary of Contemporary English - duty

~ n 1 »STH YOU HAVE TO DO« something that you have to do because it is morally or legally right + to/towards  (Ian felt a sense of duty towards his parents.) have a duty to do sth/be your duty to do sth  (The company has a duty to its shareholders to accept the highest bid. | As Christians it's our duty to help the less fortunate. | do your duty)  (You must do your duty and report him to the police. | be (in) duty bound to do sth (=have a duty to do something)) 2 »PART OF YOUR JOB« C usually plural, something you have to do as part of your job or because of your social position  (Your duties will also include coordinating secretarial support to the Head of Planning. | medical/official etc duties)  (Illness prevented her from carrying out her official duties. | report for duty (=go somewhere and officially say you are ready to work))  (Private Jones reporting for duty, Sir.) 3 be on/off duty to be working or not working at a particular time, especially doing a job which people take turns to do so that someone is always doing it  (It was the same nurse who was on duty when you had your accident. | be on night duty)  (Helen is on night duty all next week.) 4 »TAX« a tax you pay on something you buy  (The duty on wine has gone up. | customs duty (=tax paid on goods coming into the country))  (- see also death duty, stamp duty, tax1) 5 do duty as/for sth to be used as something