duty

1. (countable, uncountable) That which one is morally or legally obligated to do.Examples: "Do your duty by me! -No, we don't have a duty to keep you abreast."; "1805, 21 October, Horatio Nelson England expects that every man will do his duty."; "Captain Edward Carlisle[…]felt a curious sensation of helplessness seize upon him as he met her steady gaze,[…]; he could not tell what this prisoner might do. He cursed the fate which had assigned such a duty, cursed especially that fate which forced a gallant soldier to meet so superb a woman as this under handicap so hard."Synonyms: obligationcountableuncountable

2. (uncountable) The state of being at work and responsible for or doing a particular task.Examples: "I’m on duty from 6 pm to 6 am."uncountable

3. (countable) A tax placed on imports or exports; a tariff.Examples: "customs duty; excise duty"countable

4. (obsolete) One's due, something one is owed; a debt or fee.Examples: "Take that which is thy duty, and goo thy waye."countableobsoleteuncountable

5. (obsolete) Respect; reverence; regard; act of respect; homage.Examples: "my duty to you"; "It [the letter] was written with a plain, unaffected, homely piety that I knew to be genuine, and ended with ‘my duty to my ever darling’—meaning myself."countableobsoleteuncountable

6. (engineering) The efficiency of an engine in work done per unit of fuel; particularly, the number of pounds of water which a steam pumping engine can raise one foot by burning one bushel or hundredweight of coal.countableuncountable