a moral or legal obligation; a responsibility

it's my duty to uphold the law

she was determined to do her duty as a citizen

a strong sense of duty

a task or action that one is required to perform as part of one's job

the queen's official duties

your duties will include operating the switchboard

Juliet reported for duty

a payment levied on the import, export, manufacture, or sale of goods

a 6 per cent duty on imports

goods subject to excise duty

the measure of an engine's effectiveness in units of work done per unit of fuel