Noun
Lagrange point (plural Lagrange points)
(astrophysics, orbital mechanics) A point in an orbital configuration of a two-body system where a small object affected only by gravity can theoretically be stationary relative to the two larger objects.
Mathematically, the Lagrange points represent solutions to a restricted form of the three body problem in which the mass of one object is assumed negligible compared to that of the two principal bodies—as, for example, an artificial satellite and the Earth-Moon system.
Upon launch, the probe will proceed to a stable position at Earth’s L1 Lagrange point. Source: Internet