An Etymological Dictionary of Astronomy and Astrophysics

Acoustic waves trapped inside stars, which act as a resonating cavity, exhibiting millions of oscillation modes or standing waves. Same as → pressure mode. P-mode oscillations in the Sun have frequencies in the 0.2-5.5 mHz range. They are particularly intense in the 2-4 mHz range, where they are often referred to as solar “5-minute oscillations.”
See also → pulsation mode.

See also: P, referring to pressure; → mode.