Definition of "as long as" in English

Conjunction

1. Used other than figuratively or idiomatically: see as,‎ long.

   • It took three times as long as I expected .

2. Provided that, if, assuming (depending upon some condition or requirement).

   • I don't mind if he stays there, as long as he cleans up after himself when he's done.

3. For the entire duration that; while; since.

   • As long as you're here, you may as well help me with the garden.

Preposition

1. Used other than figuratively or idiomatically: see as,‎ long.

   • These meetings can last as long as three hours.