What does it mean to "lock in" an interest rate?

To "lock in" an interest rate means that it secures a borrower's interest rate for a specified period before closing on a loan. This process is crucial because it protects the borrower from potential increases in interest rates between the time of the loan application and the closing date. When a borrower locks in a rate, they are essentially agreeing to the predetermined interest rate for a particular length of time, which could be anywhere from a few days to several months, depending on the lender's policies. This assurance is especially valuable in a fluctuating market where rates can change frequently.

The other options suggest actions or guarantees that are not characteristic of a rate lock. For instance, changing an interest rate before closing is not a feature of a rate lock. Additionally, while some borrowers may aim for the lowest possible interest rate, a lock does not necessarily ensure that they will receive the lowest rate available; it merely provides security against rate increases during the specified period. Lastly, while committing to a specific lender does occur when a loan is taken out, it is not synonymous with the concept of locking in an interest rate.