Meaning

noun an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation

noun a vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system

noun having the character of a loud deep sound; the quality of being resonant

originFrom Old French resonance (French résonance), from Latin resonantia (“echo”), from resonō (“to resound”).

Etymology from Wiktionary, CC BY-SA 3.0