noun that which is due; payment.
2. duty ·noun respect; reverence; regard; act of respect; homage.
3. duty ·noun specifically, obedience or submission due to parents and superiors.
4. duty ·noun hence, any assigned service or business; as, the duties of a policeman, or a soldier; to be on duty.
5. duty ·noun that which a person is bound by moral obligation to do, or refrain from doing; that which one ought to do; service morally obligatory.
6. duty ·noun tax, toll, impost, or customs; excise; any sum of money required by government to be paid on the importation, exportation, or consumption of goods.
7. duty ·noun the efficiency of an engine, especially a steam pumping engine, as measured by work done by a certain quantity of fuel; usually, the number of pounds of water lifted one foot by one bushel of coal (94 lbs. old standard), or by 1 cwt. (112 lbs., england, or 100 lbs., united states).