EXCEPTIONS TO USING THE DEFINITE ARTICLE

There is no article:

• with names of countries (if singular)
  Germany is an important economic power.
  He's just returned from Zimbabwe.
  (But: I'm visiting the United States next week.)

• with the names of languages
  French is spoken in Tahiti.
  English uses many words of Latin origin.
  Indonesian is a relatively new language.

• with the names of meals.
  Lunch is at midday.
  Dinner is in the evening.
  Breakfast is the first meal of the day.

• with people's names (if singular):
  John's coming to the party.
  George King is my uncle.
  (But: we're having lunch with the Morgans tomorrow.)

• with titles and names:
  Prince Charles is Queen Elizabeth's son.
  President Kennedy was assassinated in Dallas.
  Dr. Watson was Sherlock Holmes' friend.
  (But: the Queen of England, the Pope.)

• After the 's possessive case:
  His brother's car. 
  Peter's house.

• with professions:
  Engineering is a useful career.
  He'll probably go into medicine.

• with names of shops:
  I'll get the card at Smith's.
  Can you go to Boots for me?

• with years:
  1948 was a wonderful year.
  Do you remember 1995?

• With uncountable nouns:
  Rice is the main food in Asia.
  Milk is often added to tea in England.
  War is destructive.

• with the names of individual mountains, lakes and islands:
  Mount McKinley is the highest mountain in Alaska.
  She lives near Lake Windermere.
  Have you visited Long Island?

• with most names of towns, streets, stations and airports:
  Victoria Station is in the centre of London.
  Can you direct me to Bond Street?
  She lives in Florence.
  They're flying from Heathrow.

• in some fixed expressions, for example:
• by car
• by train
• by air
• on foot
• on holiday
• on air (in broadcasting)
• at school
• at work
• at University
• in church
• in prison
• in bed