Glossary

The construction of a three-dimensional object from a computer-aided design, whereby material is deposited, joined or solidified under computer control, with the material being added together, layer by layer.

An overt security feature identified by sight or touch alone. See also Passive security feature.

Artificial intelligence systems that operate with a certain level of autonomy and intentionality. Unlike generative AI systems, which only respond to specific prompts or tasks given by users, agentic AI systems are designed to take independent actions, pursue goals, or make decisions based on a set of objectives or desired outcomes. This type of AI can proactively seek information, adapt to changing environments, and perform tasks without direct human oversight.

A mathematical procedure or formula for solving a recurrent problem, based on conducting a sequence of specified actions. For example, an encryption algorithm transforms data according to specified actions to protect that data. Provides the basis for many proprietary coding systems.

A mixture of more than one metal.

A human-readable character set containing both letters (A-Z) and numbers (0-9). The increased number of permutations resulting from using letters and numbers allows data to be encoded with fewer characters than if only numbers are used.

Using a wristwatch as an example, an analogue watch uses the movement of hands over a dial to represent passing time. It’s not the same thing as time itself, but an analogy of time. Sometimes contrasted with ‘digital’, a numeric representation of information.

A heat treatment to soften dies, planchettes or metal.

A security feature that does not accurately reproduce when copied or scanned using a mechanical or digital device. Includes printed security features integrated in the background of security printing which are invisible to the naked eye under normal inspection conditions but become visible or cause flaws to appear after copying or reproducing with a scanner.

Technical measures designed to prevent or detect counterfeiting and other forms of illicit trade. Not synonymous with non-secure track and trace technologies used for purely logistic purposes (codes on mail items for example).

A topcoat layer added to the surface of any number of materials, including adhesive materials such as labels and tape. The film contains a bacteria-blocking agent called Agion, produced by combining silver ions and zeolite.

A security feature that uses infrared radiation to create an emission within the visible spectrum. An anti-Stokes ink contains crystals of rare-earth metals (ytterbium thulium etc.) and glows when exposed to high-intensity IR light. Luminophores which glow green are the most commonly used.

Software on a mobile device used to link the holder to a specific web page/service.

A connection between computers or computer programmes. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build such a connection or interface is called an API specification. The term API may refer either to the specification or to the implementation.

Specially formulated ink which reacts when in contact with water-based reagents, leaving a visible mark.

The theory and development of computer systems able to perform tasks that normally require human intelligence, such as visual perception, speech recognition, decision-making, and translation between languages.

Something that is real, genuine, valid, of undisputed origin. Authentication is the process of confirming that a product, document or even person is authentic.

The process of determining that a product, document or even person is authentic.

Electronic device that primarily dispenses cash after identification of the customer, using a payment card or other device such as a mobile phone or biometric identification.

The time, on average, between the first issuance of a banknote and its withdrawal from circulation by the issuing central bank. High-value denominations usually have a longer average life than low-value ones which, due to their more frequent usage, deteriorate faster.

Arrangement according to which participants in the cash cycle (eg. banks or CITs) may hold cash inventories at defined locations in the name of the central bank or receive financial compensation from the central bank. This mechanism reduces the costs of inventories for participating commercial entities. See also Notes held to order (NHTO).

Placing a paper strap around a set of banknotes (usually in bundles of 100, 200, or 250 notes of the same denomination), to hold them together.

An international financial institution owned by central banks that ‘fosters international monetary and financial cooperation and serves as a bank for central banks’.

A type of negotiable promissory note, issued by a bank or other licensed authority, payable to the bearer on demand. Often referred to as a bill in the US.

A variant of polypropylene, a thermoplastic polymer that forms an ideal printing surface for labels and banknotes.

A component in a mixture (such as ink) that provides two distinctive emission spectra when excited by two different wavelengths.

A system used to produce void pantographs. Consists of two-dot patterns of differing sizes that allow a desired message or image to appear when an original document is copied. The system plays off the physical limitations of the optical systems in copiers and scanners. The little dots are sized below the optical resolution and thereby disappear when copied, while the larger dots are preserved and subsequently stand out visually.

A low-grade alloy used for some minor coin issues, usually consisting of a mixture of silver and copper, and sometimes coated with a silver wash.

Bimetallic coins consist of two metals or alloys that are bonded together, generally arranged with an outer ring around a contrasting centre. Trimetallic coins refer to coins with three rings made of three different metals or alloys.

A monetary standard in which the value of the monetary unit is defined as equivalent to certain quantities of two metals, normally gold and silver, which are independently used as legal tender, but in a fixed exchange ratio to one another.

A phenomenon exhibited by certain materials in which an incident ray of light is split into two rays, called an ordinary ray and an extraordinary ray, which are plane-(linear) polarised in mutually orthogonal planes, or circular-polarised in opposite directions (left and right).

The fraudulent act of connecting an unauthorised device to an automated teller machine in order to bypass security measures and gain access to cash. It is a type of cyber attack in which the attacker has little or no prior knowledge of the internal workings of the target system.

A piece of coin-shaped metal that is stamped and made into a coin.

A printing method consisting of two blanket cylinders through which a sheet of paper is passed and printed on both sides.

Security ink containing dyes which, in combination with a solvent, penetrates the paper substrate so that any attempt at mechanical erasure will cause visible damage to the document.

A method of creating a raised design without the use of ink. Typically, two metal dies are used for this process: one with raised detail, and another with matching but recessed detail.

Primarily denotes bank account balances.

The diffractive principle by which a layered stack of parallel reflecting surfaces of alternate higher and lower refractive index will reflect a beam of light, only when the reflected wavefronts are of an appropriate wavelength and orientation to produce constructive interference.

Any hologram in which the Bragg condition is preferential to the grating condition in forming the image. See also Volume hologram.

Text readable by touch, consisting of raised dots. Often used on cardboard outer packs and mandatory in some jurisdictions.

Ten straps of banknotes are commonly called a brick.

The raised areas of paper between the windows of a security thread.

A conglomerate of small chunks of shredded banknotes compressed or stuck together by the use of a binder. Banknotes not fit for circulation are destroyed in this way, and the compacting of the notes into briquettes facilitates the handling of this waste.

Currency issued by a subsequently defunct bank. Also referred to as obsolete banknote.

Physical gold, silver, or other precious metals of high purity, often kept in the form of bars, ingots, or coins. Bullion can sometimes be considered legal tender, and is often held as reserves by central banks or institutional investors. Bullion products are considered investment products and are traded at the daily price for the metal they contain.

A set of normally five or 10 banknote straps of usually 100 notes each.

A form of surface preparation on proof or uncirculated coin blanks, using steel balls and detergent to remove any unwanted water marks from the surface of the blank.

The process of using hard pressure rollers to finish, glaze or smooth a sheet of material such as paper, textiles, or plastics.

Traditional term used to describe money in physical form such as banknotes and coins. Starting to be used to describe value held in a digital format.

Processing centre for large volumes of cash, often in facilities with special security and logistic characteristics. Cash centres can be operated by a central bank or a commercial entity (usually a bank or cash-in-transit company).