Collector glossary

A manufacturer's designation for a specific movement design, usually including its size and layout.

Related: Movement

Any function of a timepiece beyond the display of hours, minutes and seconds.

Related: Chronograph

The mechanism that releases the gear train in regulated steps and delivers impulse to the oscillator.

Related: Lever, Balance

The engraved metal tool that transfers a design to a planchet under pressure.

Related: Planchet, Die variety

The space beneath the main design on a coin, often separated by a line and used for a date or mint mark.

From Greek ex ergon, outside the work.

Related: Mint mark, Obverse

A letter, symbol or monogram identifying the mint that struck a coin.

Related: Exergue

The principal face of a coin or medal, usually bearing the portrait or the primary authority of the issuer.

From Latin obversus, turned towards.

Related: Reverse, Exergue

The blank metal disc on which a coin is struck.

Related: Die

A coin struck from original dies at a date later than the original issue.

Related: Die

The secondary face of a coin or medal, opposite the obverse.

Related: Obverse

An official mark struck on precious metal to certify its fineness, and often its assay office and date.

Related: Maker's mark

The documented ownership history of an object.

Related: Attribution

Issued without perforations, requiring separation by cutting.

Related: Perforation

Additional printing applied to an already-issued stamp, often changing its use, country or value.

Related: Surcharge

The pattern of holes punched between stamps to allow separation, measured in holes per 2 centimetres.

Related: Imperforate

An overprint that alters the face value of a stamp.

Related: Overprint

A banknote printed to replace one spoiled in production, usually identifiable by a distinct prefix or a star in the serial number.

Related: Serial number prefix

A design formed in paper during manufacture by varying its thickness, visible in transmitted light.

Related: Security thread