Stand in line (4)
'stand in line' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for wait that I've seen before include "Hold on" , "Remain in expectation" , "Be patient" , "Delay, stand by" , "Attend, expect" .)
(Another definition for queue up that I've seen is " Form line when waiting".)