Hypertext Webster Gateway: "idolum"
From Webster's Revised Unabridged Dictionary (1913) (web1913)
Idolum \I*do"lum\, Idolon \I*do"lon\, n.; pl. {Idola}. [L. See
{Idol}; cf. {Eidolon}.]
Appearance or image; a phantasm; a spectral image; also, a
mental image or idea.
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