godan verb (-ku), intransitive verb
resound loudly (thunder, etc.)
Archaic intransitive verb for a loud, echoing sound, especially thunder. Not used in modern Japanese; replaced by とどろく or 響く.
古語では、雷がはたたくと表現した。
In classical Japanese, thunder was described as はたたく.
Modern common verb for a loud rumbling or roaring sound, including thunder.
Modern verb for echoing or resounding; broader than はたたく and not limited to thunder.
The exact derivation is uncertain; it is an archaic mimetic or sound-symbolic verb related to the sound of thunder.