Station

A planet cannot go from forward to backward without pausing. At each end of a retrograde period it stations: its motion through the zodiac slows to zero and it hangs at one degree, for days in Mercury's case, for weeks with the slow planets. The station that opens the backward stretch is the retrograde station; the one that ends it is the direct station.

A station concentrates a planet's whole agenda on one degree for that entire stretch of days, and the transit literature is unusually unanimous about the result: a planet stationing on a natal point is the strongest form of that transit, stronger than an ordinary pass. That is why, in this app's transit notes, standing still outranks moving backward.

A practical habit: when a station is coming, check the degree it lands on against your own chart. If nothing there receives it, it is mostly a calendar curiosity. If something does, that week deserves your attention.