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1610s, "act of clearing or refining" (especially of liquid substances), from French clarification, from Late Latin clarificationem (nominative clarificatio), noun of action from past participle stem of clarificare (see clarify). The meaning "statement revising or expanding an earlier statement but stopping short of a correction" is attested by 1969, originally in newspapers.
early 14c., "make illustrious, make known," from Old French clarifiier "clarify, make clear, explain" (12c.), from Late Latin clarificare "to make clear," also "to glorify," from Latin clarificus "brilliant," from clarus "clear, distinct" (see clear (adj.)) + root of facere "to make, do" (see factitious).
Meaning "make clear, purify" is from early 15c. in English; intransitive sense of "grow or become clear" is from 1590s. Figurative sense of "to free from obscurity" is from 1823. Related: Clarified; clarifying.