Толковый словарь английского языка Oxford English Reference - spectre

n. (US specter) 1 a ghost. 2 a haunting presentiment or preoccupation (the spectre of war). 3 (in comb.) used in the names of some animals because of their thinness, transparency, etc. (spectre-bat; spectre-crab). Phrases and idioms Spectre of the Brocken a huge shadowy image of the observer projected on mists about a mountain-top (observed on the Brocken in Germany). Etymology: F spectre or L spectrum: see SPECTRUM