A definite article indicates that its noun is a particular one which is identifiable to the listener. It may be something that the speaker has already mentioned, or it may be something uniquely specified. The definite article in English, for both singular and plural nouns, is the.
The children know the fastest way home.
The sentence above refers to specific children and a specific way home; it contrasts with the much more general observation that:
Children know the fastest ways home.
The latter sentence refers to children in general and their specific ways home. Likewise,
Give me the book.
refers to a specific book whose identity is known or obvious to the listener; as such it has a markedly different meaning from
Give me a book.
which does not specify what book is to be given.
The definite article can also be used in English to indicate a specific class among other classes:
The cabbage white butterfly lays its eggs on members of the Brassica genus.
However, recent developments show that definite articles are morphological elements linked to certain noun types due to lexicalization. Under this point of view, definiteness does not play a role in the selection of a definite article more than the lexical entry attached to the article.[3][4]
The definite article is sometimes also used with proper names, which are already specified by definition (there is just one of them). For example: the Amazon, the Hebrides. In these cases, the definite article may be considered superfluous. Its presence can be accounted for by the assumption that they are shorthand for a longer phrase in which the name is a specifier, i.e. the Amazon River, the Hebridean Islands. Where the nouns in such longer phrases cannot be omitted, the definite article is universally kept: the United States, the People's Republic of China. This distinction can sometimes become a political matter: the former usage the Ukraine stressed the word's Russian meaning of "borderlands"; as Ukraine became a fully independent state following the collapse of the Soviet Union, it requested formal mentions of its name omit the article. Similar shifts in usage have occurred in the names of Sudan and both Congo (Brazzaville) and (Kinshasa); a move in the other direction occurred with The Gambia.
Some languages also use definite articles with personal names. For example, such use is standard in Portuguese: a Maria, literally: "the Maria" [but this is not possible in Hindi names such as "the Sandeep," " a Sandeep". It also occurs colloquially in Spanish, German and other languages, and is sometimes heard in Italian. In Hungary it is considered to be a Germanism
