Definitions

1. preposition

extending or lying from one side to the other side of something; from one side of something to the other side, especially in a straight line.

“The train traveled across the country in just a few hours.”

2. adverb

from one side to the other side of something; in a direction from side to side.

“The ball rolled across the floor and hit the wall.”

3. verb

to extend or lie from one side to the other side of something; to cross over something, especially in a straight line.

“The river will flood the city if it rains across the valley.”