The point in an ellipticalorbit around the moon that passes closest to the moon.
1963, Lunar Flight Handbook - Part 1, Trajectory sensitivities are determined for ü=3hr and the first adjustment method is used to calculate that a midcourse correction AV_ = 7.3m/sec is required to correct to the nominal pericynthion point and time.
1964, G. Kimball Miller, Jr., A simplified guidance scheme for aborting lunar landings, The nominal landing trajectory used in this study consists of applying constant thrust at the pericynthion of the synchronous orbit and performing a gravity-turn descent to a point about 5,500 feet above the lunar surface.
2014, Victor Szebehely, Celestial Mechanics and Astrodynamics , Because of the "requirement" that the pericynthion of this type of trajectory lie on the earth-moon axis, the pericynthion loci of realistic panes pass through or very close to the earth-moon axis regardless of iVTL.
2015, Zhigang Fang, Energy Science and Applied Technology, The pericynthion's distance of 15 km and the apocynthion's distance of 100 km are known.