Yup, slight mix-up. Gravity waves are waves in the ocean and atmosphere (or other fluid bodies) where Earth's gravity is the restoring forces that causes wave propagation. Gravitational waves are the waves in spacetime caused by powerful astronomical events like black hole mergers.
I don't think I understand. Aren't all ocean waves caused by/dependent on gravity?
Sure, all the water in the ocean is affected by gravity.
However, there are many different types of waves in physics, usually described by some form of wave equation[1]. And for some of those, body forces[2] like gravity doesn't play a direct role.
A relevant example is acoustic waves[3], which are the propagation of changes in pressure. In that case, the only thing gravity is doing is confining the water to a single body through which the acoustic wave can propagate, it doesn't affect the propagation otherwise as such.
[1]: https://en.wikipedia.org/wiki/Wave_equation
[2]: https://en.wikipedia.org/wiki/Body_force
[3]: https://en.wikipedia.org/wiki/Acoustic_wave_equation
There are pressure waves in the ocean too.
wind, boats, whales, current interference/interfaces, cthlulu rolling over...