The short answer
A rate lock is an agreement covering a specific rate and other stated terms for a defined period, subject to its conditions. A quote without a confirmed lock is not the same thing.
Ask for the terms in writing
Confirm the interest rate, points or credits, lock expiration, loan structure, and conditions. Ask whether the quoted rate is actually locked and what action establishes the lock.
Plan around the expiration
The lock period and the transaction timeline need to fit. Ask what happens if closing is delayed, whether an extension is available, and who pays any associated cost under the agreement.
Changes can still matter
A change to the loan amount, credit profile, property, program, or other material facts may affect pricing or eligibility. A lock does not remove underwriting requirements or guarantee closing.
Sources and further reading
CFPB: mortgage and homebuying resourcesEducational content for review. Financing is subject to program availability, eligibility, underwriting, and approval. This is not a loan commitment or a rate quote.