PHENOM'ENON, noun plural phenomena. [Gr. to appear.] In a general sense, an appearance; any thing visible; whatever is presented to the eye by observation or experiment, or whatever is discovered to exist; as the phenomena of the natural world; the phenomena of heavenly bodies, or of terrestrial substances; the phenomena of heat or of color. It sometimes denotes a remarkable or unusual appearance.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI