Across means from one side to the other side of something. When you walk across a street, you go from one side to the other. When a bridge stretches across a river, it connects both banks. When you draw a line across a page, your pencil travels from one edge to the opposite edge.

The word helps us describe position and movement through space. A message might travel across the ocean, or news might spread across the country. You might look across the classroom at a friend, or notice birds flying across the sky.

Across can also mean on the opposite side: “My best friend lives across the street from me.” In this sense, it describes where something is located in relation to something else.

Sometimes across appears in phrases that mean “everywhere” or “throughout,” like when a teacher says “Students across the school are excited about field day.” Here it means students in every part of the school, not literally moving from side to side.

When you go across something, you're essentially crossing it.