- thunder (n.)
- mid-13c., from Old English þunor "thunder, thunderclap; the god Thor," from Proto-Germanic *thunraz (source also of Old Norse þorr, Old Frisian thuner, Middle Dutch donre, Dutch donder, Old High German donar, German Donner "thunder"), from PIE *(s)tene- "to resound, thunder" (source also of Sanskrit tanayitnuh "thundering," Persian tundar "thunder," Latin tonare "to thunder"). Swedish tordön is literally "Thor's din." The intrusive -d- also is found in Dutch and Icelandic versions of the word (compare sound (n.1)). Thunder-stick, imagined word used by primitive peoples for "gun," attested from 1904.
- thunder (v.)
- 13c., from Old English þunrian, from the source of thunder (n.). Figurative sense of "to speak loudly, threateningly, or bombastically" is recorded from mid-14c. Related: Thundered; thundering. Compare Dutch donderen, German donnern.
