article (n.)

c. 1200, "separate parts of anything written" (such as the statements in the Apostles' Creed, the clauses of a statute or contract), from Old French article (13c.), from Latin articulus "a part, a member," also "a knuckle; the article in grammar," diminutive of artus "a joint" (from PIE *ar(ə)-tu-, suffixed form of root *ar- "to fit together").

The meaning "literary composition in a journal, etc." (independent and on a specific topic, but part of a larger work) is recorded by 1712. The older sense is preserved in Articles of War "military regulations" (1716), Articles of Confederation (U.S. history), etc. The extended meaning "piece of property, material thing, commodity" (clothing, etc.) is attested by 1796, originally in rogue's cant.

The grammatical sense of "word used attributively, to limit the application of a noun to one individual or set of individuals" is from 1530s, from this sense in Latin articulus, translating Greek arthron "a joint." The part of speech (with different meanings in ancient Greek and modern English) was so called on the notion of the "pivots" or "joints" on which the propositions in a sentence are variously tied together.