c.1200, "separate parts of anything written" (e.g. the statements in the Apostles' Creed, the clauses of a statute or contract), from Old French article (13c.), from Latin articulus, diminutive of artus "a joint" (from PIE *ar-tu-, from *ar- "to fit together;" (see arm (n.1)).
Meaning extended to "a small division," then generalized to "item, thing." Older sense preserved in Articles of War "military regulations" (1716) and Articles of Confederation (U.S. history). Meaning "literary composition in a journal, etc." (independent, but part of a larger work) first recorded 1712. Meaning "piece of property" (clothing, etc.) first attested 1796, originally in rogue's cant.