The definite article THE is the most frequent word in the English language. Most students learning the language have difficulty understanding when and why we use it. Probably, this is caused by the need in most languages to determine whether a noun is masculine or feminine while the gender of nouns in English is practically non-existent. Here are a few indicators of its use:
We use the Definite Article in front of a noun when we believe the hearer/reader knows exactly what we are referring to.
A - because there is only one:
The Pope comes from Argentina.
The moon influences the tides.
The Queen of England is the longest reigning monarch.
This is why we use the definite article with a superlative adjective:
He is the oldest boy in the class.
It is the most modern building in the town.
B - because we have already mentioned it:
A woman who fell 10 metres from Morton Peak was lifted to safety by a helicopter. The woman fell while climbing.
The rescue is the latest in a series of incidents on Morton Peak. In January last year two men walking on the peak were killed in a fall.
C - because there is only one in that place or in those surroundings:
We live in a small village next to the pub. (the pub in our village)
Dad, can I borrow the car? (the car that belongs to our family)
When we stayed at my uncle’s house we went to the beach every day. (the beach near my uncle’s house)
Look at the man in the blue shirt over there. (the man I am pointing at)
We also use the Definite Article:
D - to say something about all the things referred to by a noun:
The dog is a domestic animal = Dogs are domestic animals
The koala is found only in Australia = Koalas are found only in Australia
The heart pumps blood around the body = Hearts pump blood around bodies
E - We use the definite article in this way to talk about musical instruments:
Joe plays the saxophone really well = Joe can play any saxophone
She is learning the piano = She is learning to play any piano
F - to refer to a system or service:
the Underground is always busy
I heard it on the radio this morning
You should call the police
G - With adjectives like rich, poor, elderly, unemployed, etc. to talk about groups of people:
Life can be very hard for the poor
I think the rich should pay more taxes
She works for a group to help the disabled
H - The definite article with names:
We do not use the definite article with names:
William Shakespeare wrote Hamlet. Paris is the capital of France. China is in Asia.
But we do use the definite article with:
i) Countries whose names include words like kingdom, states or republic: the United Kingdom; the Kingdom of Nepal; the United States; the People’s Republic of China.
ii) Countries which have plural nouns as their names: the Netherlands; the Philippines
iii) Geographical features, such as mountain ranges, groups of islands, rivers, seas, oceans and canals: the Himalayas; the Canaries; the Atlantic; the Atlantic Ocean; the Amazon; the Panama Canal.
iv) Newspapers: The Times; The New York Herald
v) Well known buildings or works of art: the Louvre; the Taj Mahal; the Mona Lisa;
vi) Organisations: the United Nations; the European Union
vii) Hotels, pubs and restaurants*: the Savoy; the Savoy Hotel; the Crown
viii) Families: the Clinton's, the Kennedy's, etc.
Note: We do not use the definite article if the name of the hotel or restaurant is the name of the owner