By Cathie Ericson | Realtor.com
http://www.realtor.com/advice/finance/what-is-a-mortgage-rate-lock/
When you lock your doors at night, you think, “Phew, I’m safe!” Locks mean safety. Locks mean security. And it turns out the same is true in the world of home loans, where you may encounter the term “mortgage rate lock.” So what exactly does this refer to?