Meanings of speculum include:

• A medical tool used for examing body cavities; see Speculum (medical).
• A small metal mirror used for telescopes.
• The secondary feathers on the inner part of a duck's wing which are often brightly coloured; see speculum feathers.
• A journal of medieval studies, published by the Medieval Academy of America ; see Speculum (journal) .
• Speculum metal is an alloy containing copper and tin at least.
• Ophrys speculum is a species of ground orchid.

The titles of a number of medieval books also include the word speculum:

• Speculum alchimiae , written by Roger Bacon.
• Speculum astronomiae , written by Albertus Magnus.
• Speculum ecclesiae , written by Edmund Rich.
• Speculum historiale , written by Vincent de Beauvais.
• Speculum judiciale , written by Guillaume Durand.
• Speculum meditantis , written by John Gower.
• Speculum perfectionis , written by Brother Leo .
• Speculum stultorum , written by Nigel de Longchamps (also Nigel Wireker)