Talking about the zero article is useful when we’re describing how to use articles. But essentially when we talk about the zero article we mean that we do not use any article in front of a noun. In other words, we do not use a/an or the.
There are a lot of rules about when we don't use articles. Here are some of them:
With names of countries : (if singular)
India is now an important economic power.
He's just returned from Spain. (But: he's 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):
Gareth's coming to my birthday party.
John Steed is my hero. (But: We're having lunch with the Dawsons 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 wife.
With professions :
Engineering is a useful career.
He'll probably go into medicine.
With names of shops :
I buy all my Christmas cards at Smith's.
Can you go to Boots for me?
With years :
1948 was a wonderful year.
Do you remember 1995?
With name of sports :
Golf is a very pleasant game.
I like playing football at the weekend.
With academic subjects:
My friend Bob is good at history.
I am really interested in Mathematics.
With uncountable nouns :
Rice is the main food in Asia.
British people often drink Milk added to their tea.
War is destructive.
With the names of individual mountains, lakes and islands :
Mount Everest is the highest mountain in the world.
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 tell me the way to Bond Street?
She lives in Florence.
They're flying from Heathrow.
In some fixed expressions:
on air (in broadcasting)