The length of time for which something exists or is current or valid.
The length of time for which an organism lives.
Some clams have lifespans far longer than those of human beings.
The time when something happens.
Need; requirement, necessity.
Something which causes something else; a cause.
A reason or excuse; a motive; a persuasion.
A special event or function.
A particular happening; an instance or time when something occurred.
An occurrence or state of affairs which causes some event or reaction; a motive or reason.
A favorable opportunity; a convenient or timely chance.
To cause; to produce; to induce