combination, cylinder, deadbolt (esp. AmE), mortise, Yale™ (BrE)
The hotels replaced their mortise locks on guest rooms with magnetic card readers.

electronic
safety
Most cars are now fitted with child safety locks on the back doors.
safety locks for handguns

gun (AmE), trigger
trigger locks for guns

bicycle, bike (informal)
door, window

fit
We had new locks fitted after the burglary.

break, force, pick
open, turn
He turned the lock and pushed the door open.

check
She ran around the house, checking all the locks

insert the key in the lock, turn the key in the lock
under lock and key
Prisoners are kept under lock and key 24 hours a day.

stray
She flicked a stray lock of hair off her face.

flowing
She had long flowing locks and blue eyes.

blonde, chestnut, golden, etc.
curly
He ran a hand through his curly brown locks.

carefully
He carefully locked the door behind him.

automatically, electronically
The door locks automatically.

forget to

be firmly locked, be securely locked
keep sth locked
Keep your garage securely locked.

away, in
I was terrified they would lock me in again.

in
I locked myself in the bathroom.

be safely locked, be securely locked
All the valuables were safely locked away.

Lock is used with these nouns as the subject:
eye, key, wheel

Lock is used with these nouns as the object:
bike, box, briefcase, car, closet, door, drawer, elbow, flat, gate, jaw, safe, vault