argument of perigee
Also found in: Acronyms, Wikipedia.
argument of perigee[′är·gyə·mənt əv ′per·ə·jē]
The angle or arc, as seen from a focus of an elliptical orbit, from the ascending node to the closest approach of the orbiting body to the focus; the angle is measured in the orbital plane in the direction of motion of the orbiting body. Also known as argument of perihelion.