mid-14c., "written account or record," from Old French copie (13c.) and directly from Medieval Latin copia "reproduction, transcript," from Latin copia "an abundance, ample supply, profusion, plenty," from assimilated form of com "with" (see com-) + ops (genitive opis) "power, wealth, resources," from PIE root *op- "to work, produce in abundance."
Sense extended 15c. to any specimen of writing, especially MS given to a printer to be reproduced in type (Caxton, late 15c.). Meaning "a duplication, imitation, or reproduction" written or otherwise is from late 14c. Meaning "one of a set of reproductions containing the same matter" is from 1530s.
Copy-boy, one who takes copy from the writer to the printer, is from 1888. The newspaper copy-desk, where copy is edited for printing, is from 1887; copy-editor is attested from 1889.
The "copy desk" is the managing editor's literary inspection field, his last check by which the work of all editorial departments is gauged, the final balance where the brain product of the entire working force of the paper is weighed and judged. [The Journalist, May 21, 1892]
word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.
Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.
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Definitions of copyist from WordNet
someone employed to make written copies of documents and manuscripts;