Definition of "send in" []

• Mail in; cause to be delivered (verb)
• Give one's name or calling card to a servant when making a formal visit (verb)

WordNet. Princeton University. 2010.

• "“Maybe we could send in a torpedo loaded with a batch of P-38s?”"
• "The ones I will write up and send in an e-mail to the New Hampshire Gazette."
• "Over the next two days, we set up tents, we women, we organize feeding schedules and sentry duty, aware always of the possibility that the government is going to send in the RATs."