Joseph Knibb Oak Longcase Clock, circa 1680

• Anchor Escapement - An anchor escapement is a type of mechanical escapement used in clocks and watches. It is a refinement of the older verge escapement, which was used in early mechanical timekeeping devices. The anchor escapement is characterised by the use of an anchor-shaped pallet that rocks back and forth, alternately locking and releasing the escape wheel. This action allows the movement of the watch or clock to be regulated, producing the characteristic tick-tock sound that is associated with mechanical timekeeping devices. The anchor escapement is generally more accurate and reliable than the verge escapement, and it is still used in many modern clocks and watches today.
• Spandrel - An architectural term that in horology refers to the triangular ornamental decoration in the corners of of the dial plate. The spandrels are usually of cast brass and may be additonally chased and engraved. On painted dial clocks the spandrels are also usually painted.
• Date Aperture - A date aperture is a cut out section in the face of a watch or clock, displaying the day of the month.
• Circa - A Latin term meaning 'about', often used in the antique trade to give an approximate date for the piece, usually considered to be five years on either side of the circa year. Thus, circa 1900 means the piece was made about 1900, probably between 1895 and 1905. The expression is sometimes abbreviated to c.1900.
• Hood - In longcase clocks, the hood is the wooden case that surrounds the works and dial, and includes the glass front, which is usually hinged, so the door can be opened to wind the clock or adjust the time. In 18th and 19th century longcase clocks the hood usually slides forward for removal, allowing access to the works.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• Oak - Native to Europe and England, oak has been used for joinery, furniture and building since the beginning of the medieval civilisation. It is a pale yellow in colour when freshly cut and darkens with age to a mid brown colour.
  
  Oak as a furniture timber was superceded by walnut in the 17th century, and in the 18th century by mahogany,
  
  Semi-fossilised bog oak is black in colour, and is found in peat bogs where the trees have fallen and been preserved from decay by the bog. It is used for jewellery and small carved trinkets.
  
  Pollard oak is taken from an oak that has been regularly pollarded, that is the upper branches have been removed at the top of the trunk, result that new branches would appear, and over time the top would become ball-like. . When harvested and sawn, the timber displays a continuous surface of knotty circles. The timber was scarce and expensive and was used in more expensive pieces of furniture in the Regency and Victorian periods.

This item has been included into following indexes:

• clocks, grandfather / longcase, type - other 181
• Knibb Family, Britain - clocks, maker or retailer 1