Geosynchronous - $T$ is 24 hours (or equal to the period of rotation for the orbiting body)
Geostationary - special case of geosynchronous, where the orbit is equatorial, i.e. inclination of $0°$.
Note that inclination means relative to the equatorial orbit.
Sun synchronous
For example, if we are rocketing, we can increase $v$ with a booster rocket, so they will spiral outwards.
We can use this booster rocket to achieve a specific orbit, once at the correct height (this requires maintaining a new velocity)
If you don't change the velocity after going to a different height, then you may have an elliptical orbit.
In real life we would use a retrograde booster.
But from $v^{2}=\frac{GM}{r^{2}}$, a lower $r$ means $v$ must be greater.
This can be seen as an energy conversion, i.e. your $E_{p}$ is being converted to $E_{k}$ as you go closer to the body of mass, so you have a greater velocity.
If you don't correct for a faster velocity, you will die :(
Catalogue of Earth Satellite Orbits
