cut someone in
1. Literally, to slice or carve something. That vegetable has a tough skin, so you'll really need to apply some pressure in order to cut into it.
2. To interrupt a dancing couple in order to change places with one of them (typically the man). In this usage, "cut in" is a set phrase. Oh, don't worry about cutting in—I was tripping all over myself on the dance floor anyway. May I cut in for a dance with this lovely lady?
3. To move ahead of someone or something in line before it is one's turn. The guy from the back of the line totally just cut in!
4. To interrupt someone or something. I'm sorry to cut in, but I have some information that might help. Mom is always using the phone in her office to cut in on my conversations!
5. To join something despite being unwelcome. Ugh, my little brother is always cutting in on my movie nights with my friends.
6. To automatically begin working; to turn on. With this new thermostat, the heat will cut in once the temperature drops below 70 degrees.
7. To use a cutting motion (typically with two knives) to add an ingredient to a mixture. In this usage, a noun or pronoun can be used between "cut" and "in(to)." The next step is to cut the shortening into the mixture.
8. slang To include one in the profits from something, such as a business venture. In this usage, the person being included is typically mentioned between "cut" and "in." They better cut me in on the deal—I came up with the original concept!
See also: cut