Aceite vs. óleo
The Spanish language possesses a rich vocabulary with several words for similar concepts, each having its own nuance. This is certainly true when talking about oil, or 'aceite' and 'óleo'. Both terms refer to a type of oil, but they differ in their specific usage and context.
Aceite
Aceite is a general term for oil in Spanish. This is the most widely used word for oil, referring mainly to cooking oils or oils derived from fruits and seeds such as olive oil, sunflower oil etc.
Voy a comprar aceite de oliva para la cena.
(I'm going to buy olive oil for dinner.)
¿Tiene aceite de coco?
(Do you have coconut oil?)
Óleo
'Óleo' refers specifically to oils that are utilized within artistic contexts. When one says 'óleo', it's often linked to paints or with anything related to art. It can also refer to essential oils, sacred oils used in religious ceremonies, or extremely fine, quality oils.
Mi pintura al óleo ganó el premio del concurso.
(My oil painting won the contest prize.)
El sacerdote usó óleo santificado durante la ceremonia.
(The priest used sanctified oil during the ceremony.)
Summary
'Aceite' and 'óleo' both refer to a kind of 'oil', yet they are used under particular circumstances. 'Aceite' is more general, typically referencing cooking oils. On the other hand, 'óleo' is more specialized, affiliated with artistic disciplines like painting, high-quality oils, or sacred context in case of religious ceremonies.