speed of sound

(Also velocity of sound.) Usually taken to mean the phase speed of an acoustic (or sound) wave.
In an ideal, stationary gas the speed of sound c is a thermodynamic property depending only on the equilibrium state of the gas and is given by

where γ is the ratio of specific heat capacities, at constant pressure and volume, respectively; R is the gas constant; and T is absolute temperature.

In seawater, a function of temperature, salinity, and pressure.