from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The quantum of acoustic or vibrational energy, considered a discrete particle and used especially in mathematical models to calculate thermal and vibrational properties of solids.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The quantum of acoustic or vibrational energy (sound), considered a discrete particle rather than a wave.
From Ancient Greek φωνή (phōnḗ, "sound") + -on. Modelled after photon. (Wiktionary)