What is the difference between credit freeze and credit lock?

A credit lock is different from a freeze. A credit freeze (aka security freeze) is governed under state laws, credit locks are not.

These are the bureaus' credit lock services. A lock is one feature that may be included with other product benefits.

http://www.experian.com/consumer-products/creditlock.html

https://www.transunion.com/product/credit-lock

http://www.equifax.com/lockandalert/