Technical
True Anomaly
The orbital element giving a satellite's angular position along its orbit, measured from perigee, at a specific moment.
True anomaly is the angle, measured at the focus of the orbit from perigee to the spacecraft's current position, that pins down where the satellite is along its path at a given epoch.
It is the time-varying element among the classical six; the other five describe the fixed geometry of the orbit while true anomaly advances continuously as the spacecraft moves.