as soon as

Short definition from Wiktionary

Conjunction

1. 1
   Used other than figuratively or idiomatically: see as, soon.
2. 2
   At the moment when; immediately (after); instantly; directly.
3. 3
   Used to indicate that the first action mentioned is as likely as, or is preferred to, the second action mentioned.

Preposition

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