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"El aceite" is a form of "aceite", a noun which is often translated as "oil". "La mantequilla" is a form of "mantequilla", a noun which is often translated as "butter". Learn more about the difference between "el aceite" and "la mantequilla" below.
el aceite()
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
1. (culinary)
2. (automobile)
la mantequilla()
A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).