transparent plastic made from nitro-celluloses and camphor, 1871, trademark name (reg. U.S.), a hybrid coined by U.S. inventor John Wesley Hyatt (1837-1900) from cellulose + Greek-based suffix -oid.
Its use as a photographic film was noted by 1889.As an adjective, "of or pertaining to motion pictures," by 1922; as a noun, figuratively, "motion pictures" from 1934. Abbreviated form cell "sheet of celluloid" is from 1933 (see cel).
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Harper, D. (n.d.). Etymology of cel. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/cel