What is meha in Spanish?

Mija is a term of endearment most of the time used by an older person to a younger girl or woman. It could have come from "Mi Hija" (my daughter). Mija when spoken lovingly by an elder to a woman or girl would most closely translate to "My dear".

Mijo for boys and Mija for girls. Mijo more closely translates to the Word "son" when used lovingly by an older person like a family friend.

Lately, especially in NYC and PR (and on a couple of TV American shows with poor Spanish speakers) I have heard it used more like, "Buddy" or "Pal" by strangers to contemporaries, not younger people.