Hi As Irving says, they all are synonymus but their usage depends on the context. "Niña" is the generic term to call a child and young female. "muchacha" and "chica" are used to designate a woman in her teens and twenties. The term "chica" makes reference specifically to a young and beatiful woman.

a "niña" is a youn girl between 4 and 13 years old. "chica", i think you could use it always taking about a female and "muchaha" is a girl between 13 and 20somethings i think.

the difference between "NIÑA, CHICA AND MUCHACHA" is that "NIÑA" is used to the girls between 6 and 13 years, and "CHICA AND MUCHACHA" is used to relate to a woman but "CHICA" is a word with more class, most education. good, i hope to have you helped?

Hello, Under definitions given by the RAE (Real Academia de la Lengua Española) all of them are synonymous. However, they could have different meanings and uses depending on culture of each country and according to the context of a conversation or a sentence. For example, in Mexico we use to call "niña" to a female child. However, we also use "niña" to call in a sweet manner to a woman we appreciate or love. Regards. ;)