speculum

• POS: Noun
• HYPHEN: spec=u=lum

CIDE DICTIONARY

speculum, n. [L., fr. specere to look, behold. See Spy.].

•  A mirror, or looking-glass; especially, a metal mirror, as in Greek and Roman archæology.  [1913 Webster]
•  A reflector of polished metal, especially one used in reflecting telescopes. See Speculum metal, below.  [1913 Webster]
•  An instrument for dilating certain passages of the body, and throwing light within them, thus facilitating examination or surgical operations.  [1913 Webster]
•  A bright and lustrous patch of color found on the wings of ducks and some other birds. It is usually situated on the distal portions of the secondary quills, and is much more brilliant in the adult male than in the female.  [1913 Webster]

Speculum metal, a hard, brittle alloy used for making the reflectors of telescopes and other instruments, usually consisting of copper and tin in various proportions, one of the best being that in which there are 126.4 parts of copper to 58.9 parts of tin, with sometimes a small proportion of arsenic, antimony, or zinc added to improve the whiteness.

OXFORD DICTIONARY

speculum, n. (pl. specula)
1 Surgery an instrument for dilating the cavities of the human body for inspection.
2 a mirror, usu. of polished metal, esp. in a reflecting telescope.
3 Ornithol. a lustrous coloured area on the wing of some birds, esp. ducks.

Idiom

speculum-metal an alloy of copper and tin used as a mirror, esp. in a telescope.

Etymology

L, = mirror, f. specere look

ROGET THESAURUS

speculum

Optical Instruments

N optical instruments, lens, meniscus, magnifier, sunglass, magnifying glass, hand lens, microscope, megascope, tienoscope, spectacles, specs, glasses, barnacles, goggles, eyeglass, pince-nez, monocle, reading glasses, bifocals, contact lenses, soft lenses, hard lenses, sunglasses, shades, periscopic lens, telescope, glass, lorgnette, spyglass, opera glass, binocular, binoculars, field glass, burning glass, convex lens, concave lens, convexo-concave lens, coated lens, multiple lens, compound lens, lens system, telephoto lens, wide-angle lens, fish-eye lens, zoom lens, optical bench, astronomical telescope, reflecting telescope, reflector, refracting telescope, refractor, Newtonian telescope, folded-path telescope, finder telescope, chromatoscope, X-ray telescope, radiotelescope, phased-array telescope, Very Large Array radiotelescope, ultraviolet telescope, infrared telescope, star spectroscope, space telescope, altazimuth mount, equatorial mount, refractometer, circular dichroism spectrometer, interferometer, phase-contrast microscope, fluorescence microscope, dissecting microscope, electron microscope, transmission electron microscope, scanning electron microscope, SEM, scanning tunneling electron microscope, objective lens, eyepiece, barrel, platform, focusing knob, slide, slide glass, cover glass, counting chamber, illuminator, light source, polarizer, reticle, cross-hairs, light pipe, fiber optics mirror, reflector, speculum, looking- glass, pier-glass, cheval-glass, rear-view mirror, hand mirror, one-way mirror, magnifying mirror, fun house, prism, diffraction grating, beam splitter, half-wave plate, quarter-wave plate, camera lucida, camera obscura, magic lantern, stereopticon, chromatrope, thaumatrope, stereoscope, pseudoscope, polyscope, kaleidoscope, photometer, eriometer, actinometer, lucimeter, radiometer, ligth detector, photodiode, photomultiplier, photodiode array, photocell, X-ray diffractometer, goniometer, spectrometer, monochrometer, UV spectrometer, visible spectrometer, Infrared spectrometer, Fourier transform infrared spectrometer, recording spectrometer, densitometer, scanning densitometer, two-dimensional densitometer, abdominoscope, gastroscope, helioscope, polariscope, polemoscope, spectroscope, abdominoscopy, gastroscopy, microscopy, microscopist.