Chache or also chaché is a word used in several regions of Spain to name the older brother, uncle and/or adult friend of the family. Possibly the origin is in the Arabic 1588; 1602; 1610; 1602; (shaquic "brother") which was expanded in English to "brother of the father" or any familiar person who is an authority for children. Its feminine is 'chacha'. See chacho, cache, cache.
From the 1960s until now, every time I've heard the word "chache" (in Madrid) it's been in reference to "big brother."
It is also used to refer to oneself
It has several uses. It may be a brother, older brother. Also uncle (brother of one of the parents). Also used to tell me, am I (del chache). In Colombia the chacho, means the best, the ACE, the champion.
In the southwest of the province of Jaén, chache is synonymous with Uncle, i.e., the brother of your father or your mother. Also used to great uncle, i.e., the brother of one of your grandparents. I would say that you used over this last.
In the region of Murcia thus we refer to our uncle, is the brother of our mother or father
CHACHE: In La Rioja, silly, without grace.
In some towns of the North-East of Albacete and Southeast of basin ( Manchuela ) older brother.