The word block has several meanings:

1. A solid piece of material with flat sides, usually shaped like a cube or rectangle. Building blocks are toys that stack together. A butcher's block is a thick wooden surface for cutting meat. City blocks are the rectangular sections of a city surrounded by streets on all sides. When you walk around the block, you're making a complete loop.
2. To stop something from moving or happening. A football player might block an opponent to protect the quarterback. A fallen tree can block a road. You can block someone on social media to prevent them from contacting you. When you block out noise, you're preventing it from distracting you.
3. A blockage or obstacle that prevents progress. Writer's block happens when an author can't think of what to write next, even though they want to. A mental block means you suddenly can't remember something you usually know, like when a math concept you understood yesterday doesn't make sense today.

The word suggests something solid that either physically takes up space or prevents movement and progress. Whether it's a concrete block holding up a building or an obstacle blocking your path, the idea of something firm and obstructive connects these meanings.