stationary point
n 1. (Mathematics) a point on a curve at which the tangent is either horizontal or vertical, such as a maximum, a minimum, or a point of inflection
2. (Astronomy) astronomy a point in the apparent path of a planet when it reverses direction
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014