WordWeight : Weighing the Words

Pronunciation : They
Part of Speech : pron.
Etymology : [Icel. ?eir they, properly nom. pl. masc. of sa, su, ?at, a demonstrative pronoun, akin to the English definite article, AS. se, se?, edh?t, nom. pl. edha. See That.]
Definition : Defn: The plural of he, she, or it. They is never used adjectively, but always as a pronoun proper, and sometimes refers to persons without an antecedent expressed. Jolif and glad they went unto here [their] rest And casten hem [them] full early for to sail. Chaucer. They of Italy salute you. Heb. xiii. 24. Blessed are they which do hunger and thirst after righteousness. Matt. v. 6.

Note: They is used indefinitely, as our ancestors used man, and as the French use on; as, they say (French on dit), that is, it is said by persons not specified.

pl.; poss. Theirs; obj. Them.
Source : Webster's Unabridged Dictionary, 1913