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"Cebolla" is a noun which is often translated as "onion", and "champiñón" is a noun which is often translated as "mushroom". Learn more about the difference between "cebolla" and "champiñón" below.
la cebolla()
A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
1. (vegetable)
el champiñón()
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
1. (culinary)
a. mushroom
Voy a cortar los champiñones en rebanadas delgadas.I'm going to cut the mushrooms into thin slices.