Locksets can have different functions and locking abilities.
A passage lock doesn’t lock, but keeps the door latched to the frame. This type of lock is typically used on closet doors.
Bedroom / Bathroom
A bedroom or bathroom lock allows for the door to be locked from inside the room. However, there is typically a way to unlock it from the outside in case of emergency.
An entry lock is a keyed handle which is the best security on exterior doors.
A storeroom lock will always be locked from the outside and will need a key to open. The inside of the lock is always unlocked for ease of exit.
A dummy knob is a non-turning handle with no locking mechanism. They are surface mounted and are often used on double doors, closets, and pantry doors.