What do arrows mean on Google search?
The tiny blue arrow appears next to the top result, and acts much like a cursor does. Using the up and down arrows, you can move the cursor to the result you want and hit enter to launch that page.
What is the arrow next to search results?
It is a marker to indicate the current position of the keyboard navigation, it points at the result which would open if you press enter. And yeah, it does move if you navigate using up/down arrow keys on your keyboard.