Thun"der (?), n. [OE. þunder, þonder, þoner, AS. þunor; akin to þunian
to stretch, to thunder, D. donder thunder, G. donner, OHG. donar, Icel.
þrr Thor, L. tonare to thunder, tonitrus thunder, Gr. to`nos a
stretching, straining, Skr. tan to stretch. √52. See Thin, and cf.
Astonish, Detonate, Intone, Thursday, Tone.] 1. The sound which follows
a flash of lightning; the report of a discharge of atmospheric
electricity.