what is the definition of sonic
Save. sonic /ËsÉËnÉªk/ adjective. sonic. /ËsÉËnÉªk/. adjective. Learner's definition of SONIC. always used before a noun. : of or relating to sound, sound waves, or the speed of sound. sonic waves. The concert was a sonic extravaganza. [=a very exciting and entertaining musical event]. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples.