Line of Direction means counterclockwise as you look down at the ballroom floor; also called line of dance.

Line of direction is important to social dancing as it lets lots of people use the same space to travel fairly quickly with a minimum of crashes. In general, ballroom dances move around the floor in line of direction. Slower traffic toward the inside, faster traffic toward the outside.

Most ballroom dances are choreographed in polar coordinates; which is to say, the directions are usually “along line of direction” or "against line of direction" or "into the center" or "out from the center".