Origin of "article" as a grammatical term

In English grammar, why is it that articles are named so? I associate the word with newspaper articles. Where did the term come from?

Solution 1:

The current definition has five main "articles":

noun

1.0 A particular item or object:
small household articles articles of clothing

2.0 A piece of writing included with others in a newspaper, magazine, or other publication:
an article about middle-aged executives

3.0 A separate clause or paragraph of a legal document or agreement, typically one outlining a single rule or regulation:
it is an offence under Article 7 of the Treaty

4.0 (articles) British A period of training with a firm as a solicitor, architect, surveyor, or accountant:
he is already in articles
it may be worth taking articles in a specialized firm

4.1 The terms on which crew members take service on a ship.

5.0 Grammar The definite or indefinite article. See also determiner (sense 2. ODO

All of these meanings are connected logically to joint, fit together in its etymology:

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, 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.

Etymonline.com emphasis mine

Articles represent a part that fits into something bigger:

• Personal articles represent part of all a person's property.
• Journal articles represent part of the full publication.
• Legal articles represent part of the complete document.
• Employment articles represent part of the work arrangement.
• Grammatical articles represent part of the noun phrase.

Grammatical articles have no meaning by themselves, but obtain meaning as part of their noun phrase. From Dissertations Moral and Critical, Volume 1, by ames Beattie in 1788:

A single word may convey the full import of a sentence. And this may happen in every part of speech ; the article and conjunction excepted, which can never stand by themselves, because they have no meaning , unless when they are joined with other words.

The grammatical article also presents a noun as a part of a larger class of items:

• fish is a noun representing a class.
• a fish is an indefinite noun which is part of the class fish
• the fish is a definite noun which is part of the class fish

Solution 2:

The first sense of article is "a separate portion of something written." - OED

This sense is the basis of most other meanings of article including the grammatical article. Grammatical article is defined in OED as:

Each of the members of a small set of words that give definiteness or indefiniteness and specificness or genericness to the application of a noun

As we covered the definition part, OED mentions that their etymon is classical Latin articulus:

joint, limb, finger, subdivision, part, point of time, juncture, critical moment, clause or section, pronoun or pronominal adjective, (definite or indefinite) article, in post-classical Latin also a multiple of ten (from 8th cent. in British sources) < artus joint ( < an Indo-European base with the sense ‘to join’ which also ultimately underlies arm n.¹, art n.¹) + -culus -cle suffix.

OED adds that the grammatical article was in Latin use after ancient Greek ἄρθρον and gives the following explanation:

For the ancient Stoic grammarians the term ἄρθρα embraced both articles and pronouns, but they differentiated two categories, calling articles ἄρθρα ἀοριστώδη ‘indefinite joining words’ and pronouns ἄρθρα ὡρισμένα ‘definite joining words’. By the time of Apollonius Dyscolus (2nd cent. a.d.) the article and the pronoun had been classified as two separate parts of speech and designated ἄρθρον and ἀντωνυμία respectively. Correspondingly the Latin grammarians (from the time of Quintilian (1st cent. a.d.)) used articulus for article and pronomen for pronoun. Latin had no articles as such, and Greek had only a definite article (ὁ , ἡ , τό the adj.). The distinction between ‘definite’ (e.g. the ) and ‘indefinite’ (e.g. a ) articles arose in the context of the description of modern Romance languages, though the terms go back ultimately (via Latin) to the Greek terms mentioned above. The English terms appear to be unknown to Palsgrave (1530) though he distinguishes two articles in French, ung and le (without giving them specific names).

According to OED, the word article (for the grammatical sense) first appears in D. Thomson's Middle Eng. Grammatical Texts (c1400):

Þat is a nown þat declines w^tartikyls and case or w^t thre diueris endyngys in a case.