1 the people, animals, or things previously named or in question (pl. of HE, SHE, IT(1)).
2 people in general (they say we are wrong).
3 those in authority (they have raised the fees).
4 disp. as a third person sing. indefinite pronoun meaning 'he or she' (anyone can come if they want to).
Etymology: ME thei, obj. theim, f. ON their nom. pl. masc., theim dat. pl. of saacute THE that
Useful english dictionary. 2012.