1
general::
1. Cause to be dispatched or delivered, as in Let's send in a letter of protest to the hiring committee. [Early 1700s] 2. Cause someone to become involved in a particular undertaking, as in This disagreement is serious; it's time to send in the lawyers, or In the final few minutes the coach sent in Richard on right wing. [Mid-1800s]
American Heritage Idioms
2
general::
Phrase(s): send someone in
Go to send someone into something.
McGrawhill's American Idioms And Phrasal Verbs