1. Of or relating to audible sound: a sonic wave.
2. Having a speed approaching or being that of sound in air, about 1,220 kilometers (760 miles) per hour at sea level.
3. Slang Extremely exciting and fast-paced: a sonic lifestyle.
[From Latin sonus, a sound; see swen- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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