An Etymological Dictionary of Astronomy and Astrophysics

1. The instantaneous linear velocity of a body moving in a circular path. It is equal to the → angular velocity multiplied by the radius: v_t = ωr.
   

2. The component of the velocity of an object, such as a star, that is at right-angles to the observer’s → line of sight; also known as transverse velocity. See also → radial velocity.

See also: → tangential; → velocity.