v.1. To be sold completely: The tickets will sell out by tomorrow.
2. To sell one's entire supply of a particular item: I'm afraid we sold out all our ice cream, kids! The hardware store sold out of plywood as the hurricane moved closer to shore.
3. To cause some supply of merchandise to be sold completely. Used in the passive: We can't get into the theater because the tickets are sold out.
4. To cause some vendor to sell its entire supply of something. Used in the passive: I wanted to buy more spoons, but the store was sold out.
5. To sell one's entire stake in a business or venture: The owners of the liquor store plan to sell out as soon as they can find a buyer.
6. To betray one's cause or colleagues, especially for money: The disloyal baseball player sold out to another team.
7. To betray someone or something, especially for money: The manager sold out his staff in order to keep his own job. Our agent sold us out when she moved to a better company and dropped us as a client.