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"On Monday" is a phrase which is often translated as "el lunes", and "Monday" is a proper noun which is also often translated as "el lunes". Learn more about the difference between "on Monday" and "Monday" below.
on Monday(
an
 
muhn
-
dey
)
A phrase is a group of words commonly used together (e.g., once upon a time).
phrase
a. el lunes
I have an appointment with my oncologist on Monday.El lunes tengo una cita con mi oncólogo.
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Monday(
muhn
-
dey
)
A proper noun refers to the name of a person, place, or thing.
proper noun
a. el lunes
(m) means that a noun is masculine. Spanish nouns have a gender, which is either feminine (like la mujer or la luna) or masculine (like el hombre or el sol).
(M)
Monday was rainy.El lunes estuvo lluvioso.
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