The and zero article

Use the when the listener can identify the person or thing. It may be mentioned before, visible, unique, or defined by extra information: Close the door. The book on the table is mine.

Some things are naturally unique in ordinary context, so they usually take the: the sun, the moon, and the internet. A superlative also normally takes the: the best friend.

Use no article, called the zero article, when plural count nouns or uncountable nouns have a general meaning: Dogs are friendly animals. Water is important. I like coffee.

Meals, languages, school subjects, and many activities often use zero article in their general meaning: We eat dinner at six. She speaks English. I like music.

Compare general and specific meaning: I like coffee means coffee in general. The coffee on the table is cold means one identifiable serving. Meaning decides whether the is needed.