v.1. To order someone to return; have someone return: He came to visit me at a bad time, so I sent him back. She sent the children back to the same school they attended the year before.
2. To return something, especially as a way of rejecting it: I went to the post office to send back the broken toaster. The steak was undercooked, and I had to send it back to the kitchen.
3. To return or reply to someone or something by mail or some other means of communication: I sent back a reply via fax. Please send a quick message back by e-mail if you can't come to the party.