1. Same as phase speed. 2. The velocity at which a wave of given frequency and wave length advances across the ocean. See dispersion relationship.

The phase velocity of a wave is the rate at which the phase of the wave propagates in space. This is the velocity at which the phase of any one frequency component of the wave will propagate. You could pick one particular phase of the wave (for example the crest) and it would appear to travel at the phase velocity.