I. before consonants usually thə, before vowels usually thē, sometime before vowels also thə; for emphasis before titles and names or to suggest uniqueness often ˈthē definite article
Etymology: Middle English, from Old English thē, masculine demonstrative pronoun & definite article, alteration (influenced by oblique cases — as thæs, genitive — & neuter, thæt ) of sē; akin to Greek ho, masculine demonstrative pronoun & definite article — more at that
Date: before 12th century
1.
a. — used as a function word to indicate that a following noun or noun equivalent is definite or has been previously specified by context or by circumstance
put the cat out
b. — used as a function word to indicate that a following noun or noun equivalent is a unique or a particular member of its class
the President
the Lord
c. — used as a function word before nouns that designate natural phenomena or points of the compass
the night is cold
d. — used as a function word before a noun denoting time to indicate reference to what is present or immediate or is under consideration
in the future
e. — used as a function word before names of some parts of the body or of the clothing as an equivalent of a possessive adjective
how's the arm today
f. — used as a function word before the name of a branch of human endeavor or proficiency
the law
g. — used as a function word in prepositional phrases to indicate that the noun in the phrase serves as a basis for computation
sold by the dozen
h. — used as a function word before a proper name (as of a ship or a well-known building)
the Mayflower
i. — used as a function word before a proper name to indicate the distinctive characteristics of a person or thing
the John Doe that we know wouldn't lie
j. — used as a function word before the plural form of a surname to indicate all the members of a family
the Johnsons
k. — used as a functon word before the plural form of a numeral that is a multiple of ten to denote a particular decade of a century or of a person's life
life in the twenties
l. — used as a function word before the name of a commodity or any familiar appurtenance of daily life to indicate reference to the individual thing, part, or supply thought of as at hand
talked on the telephone
m. — used as a function word to designate one of a class as the best, most typical, best known, or most worth singling out
this is the life
the pill
— sometimes used before a personal name to denote the most prominent bearer of that name
2.
a.
(1) — used as a function word with a noun modified by an adjective or by an attributive noun to limit the application of the modified noun to that specified by the adjective or by the attributive noun
the right answer
Peter the Great
(2) — used as a function word before an absolute adjective or an ordinal number
nothing but the best
due on the first
b.
(1) — used as a function word before a noun to limit its application to that specified by a succeeding element in the sentence
the poet Wordsworth
the days of our youth
didn't have the time to write
(2) — used as a function word after a person's name to indicate a characteristic trait or notorious activity specified by the succeeding noun
Jack the Ripper
3.
a. — used as a function word before a singular noun to indicate that the noun is to be understood generically
the dog is a domestic animal
b. — used as a function word before a singular substantivized adjective to indicate an abstract idea
an essay on the sublime
4. — used as a function word before a noun or a substantivized adjective to indicate reference to a group as a whole
the elite
II. adverb
Etymology: Middle English, from Old English thȳ by that, instrumental of thæt that
Date: before 12th century
1. : than before : than otherwise — used before a comparative
none the wiser for attending
2.
a. : to what extent
the sooner the better
b. : to that extent
the sooner the better
3. : beyond all others
likes this the best
III. preposition
Etymology: the (I)
Date: 15th century
: per 2
a dollar the dozen