Transit
A transit is the movement of a planet in the sky influencing the fixed positions in your birth chart. Transits are what most horoscopes describe.
A birth chart is fixed - it never changes. But the actual positions of planets in the sky change every day. When a planet "in todays sky" moves over a planet in your birth chart, that is a transit.
Fast-planet transits (Mercury, Venus, Mars) are short-lived - days to weeks. Slow-planet transits (Jupiter, Saturn, Pluto) last months to years and bring the big life changes.
The most important transits for most people are Saturn (career, structure, limits) and Jupiter (growth, opportunity, expansion). If you have experienced your "Saturn return" (around ages 27-30), you know what that means.
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