Éclair vs. foudre
In French, the words 'éclair' and 'foudre' are both related to the natural phenomenon of lightning. However, they refer to different aspects of it and are used in various contexts to convey distinct nuances.
Éclair
A flash of lightning, generally referring to the visible aspect of lightning.
Un éclair illumina soudain le ciel nocturne.
(A lightning bolt suddenly lit up the night sky.)
L'éclair était suivi par un grand bruit de tonnerre.
(The flash of lightning was followed by a loud thunderclap.)
Les enfants comptaient les secondes entre l'éclair et le tonnerre.
(The children counted the seconds between the lightning flash and the thunder.)
Foudre
Refers to lightning as a whole phenomenon, including both the flash and its powerful impact; it can also imply a metaphorical sense of suddenness or intensity.
La foudre a frappé un arbre près de la maison.
(Lightning struck a tree near the house.)
Il craint la foudre pendant les orages.
(He fears lightning during thunderstorms.)
Elle est tombée amoureuse comme la foudre - soudainement et intensément.
(She fell in love like lightning - suddenly and intensely.)
Summary
While 'éclair' refers specifically to the brief, visual flash seen during a lightning strike, 'foudre' encompasses the entire event including its potential impact. 'Éclair' particularly highlights the luminous aspect, whereas 'foudre' conveys power and suddenness, occasionally extending into metaphorical usages.