occasion

(noun): A favorable opportunity; a convenient or timely chance.
(noun): The time when something happens.
(noun): An occurrence or state of affairs which causes some event or reaction; a motive or reason.
(noun): Something which causes something else; a cause.
(noun): An occurrence or incident.
(noun): A particular happening; an instance or time when something occurred.
(noun): Need; requirement, necessity.
(noun): A special event or function.
(noun): A reason or excuse; a motive; a persuasion.
(verb): To cause; to produce; to induce