article vs written document

article and written document both are nouns.

Word	Noun	Adjective	Verb	Adverb
article	Yes	No	Yes	No
written document	Yes	No	No	No

article (noun)	written document (noun)
one of a class of artifacts	writing that provides information (especially information of an official nature)
nonfictional prose forming an independent part of a publication
(grammar) a determiner that may indicate the specificity of reference of a noun phrase
a separate section of a legal document (as a statute or contract or will)

article (verb)	written document (verb)
bind by a contract; especially for a training period