So what is it? Cylinder, lock, bolt?

Many of the definitions are clear, with hardly any room for interpretation. However, this is not the case with modern designations such as "access control system" or even "master key system". Whether a door can only be opened with a key or with a chip card is not clear per se from the two terms mentioned above.

To enable a clear distinction between the two via the terms, ASSA ABLOY only uses the word "master key system" to describe systems with keys. If doors are also opened using a chip card, Bluetooth or code lock, we refer to access control systems. This clear distinction is helpful because master key systems do not require a power supply on the door, while a power supply is required for access control systems.

Here, you will find a simple explanation of the most important terms:

Access control – a system that ensures only authorised persons have access to certain areas and facilities. This can be ensured via master key systems or access control systems.

Access control systems – system and products to protect against unauthorised access to sensitive areas such as offices, data centres, laboratories, cash registers, archives, production facilities, vaults, etc. In contrast to master key systems where keys are used, access conrol systems also use chip cards and fully electronic authentication media to check authorisations for access. Readers must be installed for authentication.

Backset – the backset is the distance between the front edge of the lock ( → forend) and the centre of the → locking cylinder. It is important because the forend screw must be at least as long as the backset in order to actuate the cylinder in the lock.

Bolt – a metal rod in the lock that is moved when a key is turned in the cylinder to lock or unlock the door. There is a cut-out in the → strike plate of the door frame for this purpose. Security doors can also have multiple bolts.

Cam – the part of the key that is inserted into the → locking cylinder and is "checked" by the cylinder to release the cylinder core for rotation.

Comfort function – in unfortunate situations, it may be necessary to actuate a lock from the outside even if a key is inserted and possibly turned on the inside. Cylinders with a comfort function offer the technical possibility of actuating the lock, even if a key is inserted on the other side.

Cylinder cover – additional cover on the security fitting to prevent the → locking cylinder or its core from being pulled out violently.

Cylinder or locking cylinder – exchangeable part of a lock that uses suitable technology to check whether the key can be turned and thus the bolt or the latch can be moved after a key is inserted. In the case of mechanical cylinders, the check is frequently carried out using pins, which must be pressed in by the key cam to be able to turn the locking cylinder core. The cylindercerf is  via a forend screw in the → lock and can therefore only be changed when the door is open.

Door handle – a handle on one or both sides of the door that pulls the → latch when pressed down and thus enables the door to be opened. This is sometimes also referred to as a lever, handle.

Door hinge – metal hinge on the hinge side of a door, both in the door leaf and the → door frame. Often with interlocking metal pins to prevent the door from being pried out. Door hinges with springs can close doors automatically.

Double cylinder – is a special type of → locking cylinder which can be operated from both sides with a key. A distinction is made between standard cylinders and cylinders with → convenience function.

Frame – frame in the masonry in which the door is suspended via hinges and which holds the strike plate as a counterpart to the lock.

Forend – front plate on mortise locks for guiding through the → bolt and → latch from the → lock case and for fixing the mortise lock in the door leaf with one or several fixing screws above and below the lock case.

Hinge side – the side of a door on which the hinges are normally visible.

Key alike – if two cylinders have the same → locking device (i.e. can be locked with the same key), this is referred to as key alike. This is useful for enabling the garage and entrance door to be locked with the same key or if several rooms in a company are to be accessed by a specific group of people.

Key channel – opening and guide within the → locking cylinder into which the key can be inserted.

Key head – head or handle of the key.

Key security – the degree of difficulty of being able to copy keys without authorisation and for unfair purposes. Key security is determined by the type of key (technical copy protection) and the possibility of obtaining key blanks (free key profiles and patented (= protected) key profiles).

Knob – a round, usually non-moving handle on one side of the door, used to open the door after it has been unlocked with a key

Latch (or latch bolt) – part of the lock that protrudes from the lock when the door is open and is pushed into the lock when the door is pushed closed or "latched" by pressing on an inclined surface. If the door is completely locked, a spring pushes the latch into the recess in the strike plate and thus keeps the door closed. This often takes place with a clearly audible "click". The latch can be retracted using the door handle or a key to open the door.

Lock – mechanical, often metal unit, installed in the door leaf on the front. It usually consists of the → lock case, → forend, → latch and → bolt and cut-out for the → locking cylinder. Modern locks can also be operated electrically. The lock does not include the → door handle and → cylinder. The lock secures the door against unauthorised opening.

Lock case – is the visible shell of a → lock when it is removed.

Lock picking security – describes how difficult it is to actuate a locking cylinder with a key other than the belonging key. The lock picking security can be increased with a special key profile shape, as well as with corresponding key profile controls, such as side control pins, balls or tilt elements. All measures to minimise wear in the locking cylinder and on the key also ensure a high level of lock picking security.

Locking  – this refers to the configuration of the key and cylinder, which defines how the key must be designed so that it can be turned in the cylinder. If there are several cylinders that can be locked with multiple keys, this is referred to as → key alike.

Locking cylinder – see → Cylinder

Locking system – the way in which the locking technology works. A differentiation is made between mechanical and mechatronic.

Master key system – complete system consisting of cylinders, keys and (in the case of electronic and mechatronic systems) hardware and software for programming and managing keys and cylinders. When also referring to systems with electronic locking cards, we often use the term access control systems.

Mechatronic – a term made up from mechanical and electronic that describes a technology where mechanical and electronic components interact with each other. In mechatronic → cylinders, for example, the electronics ensure that the key can be turned mechanically and the → bolt can be moved following a successful login electronically.

Mortise lock – lock with latch and bolt according to DIN 18 251 for installation in different doors. Mortise locks can have a cam, tumbler or profile cylinder locking mechanism or be mortise locks with a bathroom bolt. The most important components of a mortise lock are: → latch, → forend, → bolt, change, handle follower → lock case and tumblers.

Multi-point locking – a locking device that secures a door in several places (points) with the help of → bolts or rods. It offers increased security, because it makes it difficult for burglars to break open the door.

Reversible key – a key that can be inserted in the key channel in any direction. It has identical troughs and security features on both sides of the cam.

Scanning security – indicates how difficult it is to obtain the information to produce a duplicate key using suitable technical aids. It can be increased using recesses in several dimensions or recessed magnets.

Security card – authorisation in credit card format which is issued for a → master key system or a single → locking cylinder and only authorises the users to obtain replacement keys and/or locking cylinders for the relevant → locking or master key system.

Security fitting – a door handle set consisting of the following parts: Outside escutcheon, inner escutcheon, connecting element between outside and inner escutcheon, door handle on inner escutcheon, any door handle or fixed knob or door knob (handle plate) on outside escutcheon; where applicable with additional cover for the locking cylinder.    

Strike plate – mechanical, often metal, sturdy device in the door frame with recesses for the latch and bolt of the lock. It prevents the door from opening if the latch and/or bolt are protruding into the recesses. As security strike plate it's connected to the masonry behind the frame with wall anchors. An electric strike plate contact (bolt switch contact) can also be installed in the strike plate.