thunder – el trueno
(Pronounced trweh-noh)
To remember that thunder is pronounced trweh-noh (trueno) in Spanish, use the following mnemonic:
The thunder scared the enemy troops away. They were nowhere (trueno) to be found.

Trueno is masculine, so it's el trueno. Imagine an elephant dressed as Thor, the god of thunder.

Examples of trueno (thunder) in a sentence
El trueno me despertó en medio de la noche.
(The thunder woke me up in the middle of the night.)
Después del relámpago, escuché un trueno muy fuerte.
(After the lightning, I heard a very loud thunder.)
Los niños tienen miedo del trueno durante las tormentas.
(The children are afraid of the thunder during storms.)