The word "block" is often used as a verb. To block is to stop or prevent an action
•The police blocked off traffic on the street.
•There's a large box blocking the doorway.
•Jill's boss is blocking her promotion.
•It's illegal to block an emergency exit.
•Something is blocking the drain, so now the water won't go down.
•The website is being blocked by the government.
When the word "block" is a noun, it has a few different meanings:
•There are some nice houses and apartments on this block.
•Children like to play with blocks.
•Many houses and buildings are made with concrete blocks.
•Barbed wire is an effective block against an unlawful entry.
•I went to the deli to buy a block of cheese.