Wait On Meaning

(falconry) To fly above its master, waiting till game is sprung; said of a hawk.

Example:   I'm waiting on the light to change.
To wait for a person to do something.
  I'm waiting on you before we can leave.
To serve someone.
  Is someone waiting on you yet?
  I must wait on myself, must I?
Dr. H. More
  that ruin that waits on such a supine temper
Bible, Numbers iii. 10
  Aaron and his sons […] shall wait on their priest's office.
Used other than as an idiom: see wait,‎ on.
  The airplane had to wait on the runway for a few minutes before it could take off.