v.1. To lock a door to a place leaving someone or something inside: My parents often locked me in my bedroom as punishment. We accidentally locked in the cat when we left.
2. To guarantee something for the duration of a contract: You can lock in this interest rate for the life of the loan. When interest rates fell, I locked them in at a lower rate.
3. To bind someone by contract: The contract locks us in for two years, during which time we cannot work for anyone else. Once you sign the agreement, you will be locked in for the next ten years.
4. To invest some money in such a way that it cannot easily be converted into cash. Used chiefly in the passive: The money is locked in until I turn 65.
5. To bind in close struggle or battle. Used chiefly in the passive: The wrestlers were locked in combat. The two sides were locked in a heated debate.
6. lock in on To focus on someone or something; target someone or something: The fighter pilot locked in on an enemy target and fired. The review locked in on the crude set design and failed to mention the great acting.