Trousers – el pantalón
(Pronounced pan-tah-lon)
To remember that trousers is pronounced pan-tah-lon (pantalón) in Spanish, use the following mnemonic:
The thief was stealing his trousers, so he shouted: "Leave my pants alone!" (pantalón).

Pantalón is masculine, so it’s el pantalón. Imagine an elephant getting into a pair of trousers:

Examples of pantalón (trousers) in a sentence
Me puse los pantalones antes de salir de casa.
(I put on my trousers before leaving the house.)
¿Dónde compré este pantalón? Es muy cómodo.
(Where did I buy these trousers? They are very comfortable.)
El pantalón azul está en el armario.
(The blue trousers are in the wardrobe.)