The i/ðə/ is the only definite article in English, denoting person(s) or thing(s) already mentioned, under discussion, implied, or otherwise presumed familiar to the listener or reader. The is the most commonly used word in the English language, accounting for 7% of all words.
"The" can be used with both singular and plural nouns, with nouns of any gender, and with nouns that start with any letter. This is different from many other languages which have different articles for different genders or numbers.
In most dialects, "the" is pronounced as /ðə/ (with the voiced dental fricative /ð/ followed by a schwa) when followed by a consonant sound, and as /ðiː/ (homophonous with thee) when followed by a vowel sound or used as an emphatic form. In modern American English, however, there is an increasing tendency to limit the usage of the latter pronunciation to emphatic purposes and use the former even before a vowel.