I heard many times about "chiqui" and "chiquitita", but I can not find their translation even by Google translate. Could anyone tell me what does these two words mean? And where do they come from?
Any dictionary will tell you that chico means small and so does chiquitito since it is the diminutive of "chico".
The diminutive of chico could be formed in these three ways: Chiquito, chiquitito or chiquillo.
That being said, chiqui is not other than an abbreviation of "chiquito/a".
It is a colloquial way to call someone mainly on a familial or romantic/loving setting and it is very commonly used to refer to children or to a romantic partner usually when he/she is short.
Chiqui is the Spanish equivalent of shorty.