1. You can use the noun without any determiner at all.
• in the singular, if it is a proper noun
Boston is on the east coast.
• in the singular, if it is an uncountable noun
I can hear music.
• in the plural, if it is a countable noun
Tigers have black stripes.
When you use a plural countable noun without the article, you are seeing the noun in a general way – ‘tigers in general’.
2. You can use the noun with either of the ‘articles’, a or the:
• use a with singular, countable nouns
I can see a car.
• use the with singular countable nouns
I can see the car.
• use the with plural countable nouns
I can see the cars.
• use the with uncountable nouns
I can see the water.
The articles are the most common determiners in English. Their main job is to say whether the noun is ‘definite’ or ‘indefinite’.