The piece of furniture you sit on
Encoding Strategies:
linguistic
visual

seat
seat
+
-illa
noun ending
Silla means chair and is related to the English word seat0 turned into a Spanish noun.
silla
chair, seat
A piece of furniture with a back, for one person to sit on.
Pon las sillas alrededor de la mesaPut the chairs around the table
Busca una silla libre y siéntateFind a free seat and sit down
saddle (on a horse)
A rider's seat on a horse. Short for silla de montar (a seat for riding).
El vaquero puso la silla sobre el caballo antes de salirThe cowboy put the saddle on the horse before heading out