The - Wikipedia
The (/ðə, ðiː/ (listen)) is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers or speakers.
the - Wiktionary
(when unstressed and prevocalic). enPR: thē, IPA(key): /ði/. (when unstressed and preconsonantal). enPR: thə, IPA(key): /ðə/ (but see notes below). From Middle English the, from Old English þē ("the, that", demonstrative pronoun), a late variant of sē.