in waiting
In attendance or accompaniment, especially as upon a royal or noble personage. The Duke sent one of his servants in waiting to admit his guests into the banquet hall.
in waiting
In attendance, especially on a royal personage. For example, The prelates who were in waiting asked him to take the last rites. This usage has become less common with the diminution of royalty and royal courts but still survives. [Late 1600s]
in waiting
In attendance, especially at a royal court.