- a mirror or reflector, especially one of polished metal, as on a reflecting telescope.
- speculum metal.
- an instrument for rendering a part accessible to observation, as by enlarging an orifice.
- a lustrous or specially colored area on the wings of certain birds.
- a mirror, esp one made of polished metal for use in a telescope, etc
- an instrument for dilating a bodily cavity or passage to permit examination of its interior
- a patch of distinctive colour on the wing of a bird, esp in certain ducks
