As verbs the difference between lock and secure
is that
lock is to become fastened in place while
secure is to make safe; to relieve from apprehensions of, or exposure to, danger; to guard; to protect.
As a noun lock
is something used for fastening, which can only be opened with a key or combination.
As a proper noun Lock
is {{surname|lang=en}.
As an adjective secure is
free from attack or danger; protected.