a determiner (the in English) that implies that the thing mentioned has already been mentioned, or is common knowledge, or is about to be defined (as in the book on the table; the art of government). Compare with indefinite article.
In GRAMMAR, the technical term for the word the
when introducing a noun phrase, as in the telephone in my office
is also used, in a correlative pair, with a comparative adjective and adverb to introduce a clause: The more I exercise
, the healthier I feel
. For fuller discussion, see ARTICLE