Emily Dickinson Lexicon

SPEC'U-LUM, n. [L.; G. and D. spiegel; Sw. spegel; Dan. spejl.]

1. A mirror or looking glass.
2. A glass that reflects the images of objects.
3. A metallic reflector used in catadioptric telescopes.
4. In surgery, an instrument for dilating and keeping open certain parts of the body. – Coxe.