The perigee is the point in its orbit where the Moon, or an artificial satellite, is closest to Earth's surface.

 

Apogee

The apogee is the point in a geocentric orbit, such as that of the Moon or an Earth-orbiting spacecraft, that is furthest from Earth's surface.

 

Apogee kick motor

An apogee kick motor is a solid rocket motor, usually permanently attached to a spacecraft, which circularizes an elliptical transfer orbit by igniting at apogee (leading to the colloquial phrase 'a kick in the apogee'). First used on the early Syncom satellites in 1963–1964 to 'kick' the satellite from a geostationary transfer orbit to a geostationary orbit. Also known simply as an apogee motor.