1590s, from Latin speculum, literally "mirror," from specere "to look at, view" (see scope (n.1)).
speculum spec·u·lum (spěk'yə-ləm)n. pl. spec·u·lums or spec·u·la (-lə)
A mirror or polished metal plate that is used as a reflector in optical instruments.
An instrument that is used to dilate the opening of a body cavity for medical examination.