Are muchacha, chica, and niña interchangable?
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3 Answers
If I had to put them in age order from younger to older: niña, chica, muchacha. But that's just my personal preference.
Niña usually refers to a female child. You can also say chiquita or muchachita to convey the same meaning.
Chica and muchacha can mean girl or even a young woman.
I hope this helps.
I basically agree with usarenzo, but in Mexico I would not refer to a young woman as "muchcha" because this is how female domestic workers are called. A young professional woman, for example, would be quite offended.
But also "muchacha" is a geniric therm for a young girl en la calle, vi a una muchacha muy bonita