1. To submit or dispatch a request or order something to be delivered. I'm sending in for a new computer monitor that supposedly has the highest resolution on the market. I can fix it, but I'll have to send in for a new part.

2. To submit or dispatch something to some place in order for something to be done. In this usage, a noun or pronoun is used between "send" and "in." The built-in scanner on the printer isn't working anymore, so I'll have to send it in for repairs. It sounds like you'll need to send your watch in for an adjustment of the band.

3. To instruct or direct someone to enter some place to retrieve or receive something. In this usage, a noun or pronoun is used between "send" and "in." I'll send my intern in for the report when it's ready. Hi Martha, will you please send Tom in for his annual review?

4. To replace a player with someone else in a sporting event. In this usage, a noun or pronoun is used between "send" and "in." With such a strong lead, the coach decided to send the rookie in for the veteran quarterback. Send me in for Tom, Coach—I'm ready!