A mazer is a special type of wooden drinking vessel, a wide cup or shallow bowl without handles, with a broad flat foot and a knob or boss in the centre of the inside, known technically as the print or boss. They vary from simple wood pieces all in wood to those ornamented with metalwork, often in silver or silver-gilt. They use dense impervious woods such as maple, beech and walnut wood, and get their name from the spotted or birdseye marking on the wood (Ger. Maser, spot, marking, especially on wood; cf. measles), or possibly maserle as a name for acer campestre. They are a north European medieval tradition, mostly made from the 11th (or earlier) to the 16th centuries.
The examples that have been preserved above ground are generally of the most expensive kind, with large mounts in silver, but some archaeological sites have produced quantities of plain wood mazers, which were no doubt the most common at the time. The wreck of the Mary Rose is one example of a group find, and the Nanteos Cup a single survival. They are typically between five and eleven inches in diameter.
Ornamented types usually have a rim or "band" of precious metal, generally of silver or silver gilt; the foot and the print being also of metal. There are examples with wooden covers, sometimes with a metal handle, such as the Bute Mazer or Flemish and German mazers in the British Museum. On the outside, but generally not the inside of the metal band there is often an inscription, religious, or convivial, and the print was also often decorated with a sculpted or engraved plare, and sometimes a gem. The Bute Mazer is one of the most elaborate to survive, with a three-dimensional reclining lion rising from the base, and enamelled coats of arms in a circle around it. Saints, the religious monogram IHS, and animals, often no doubt with heraldic significance, are other common decorations of the boss. Many metal pieces that appear to be mazer bosses have been excavated. An example from York Minster grants an indulgence of 40 days remission from Purgatory for all who drink from it.