Station
A station is the moment a planet appears to stop before changing direction, either turning retrograde or turning direct, and traditional astrology reads a stationary planet as unusually emphatic.
Nothing stops in space. The apparent halt is the turning point of the same relative motion that produces retrogradation, and near it a planet's daily movement falls almost to nothing, so it can sit on the same degree for days.
That lingering is the reason for the emphasis: a planet standing still on a degree of your chart stays there far longer than a moving one would. The station direct is generally read as the more constructive of the two.
Frequently Asked Questions
How do I find a station in an ephemeris?
Look for the row where the R appears or disappears in a planet's column, then check how little it moved on the days either side.
Is a stationary planet strong?
Classical practice treats it as emphatic rather than dignified. It lingers, so whatever it touches it touches for longer.
See also
See this concept in your own chart: Free birth chart