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 (magazine).
- Speculum metal is an alloy containing copper and tin at least.
- Ophrys speculum is a species of ground orchid.
- 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.