While

Space of time, or continued duration, esp. when short; a time; as, one while we thought him innocent.

That which requires time; labor; pains.

To cause to pass away pleasantly or without irksomeness or disgust; to spend or pass; -- usually followed by away.

To loiter.

During the time that; as long as; whilst; at the same time that; as, while I write, you sleep.

Hence, under which circumstances; in which case; though; whereas.

Until; till.