Does the word hermanote mean older brother in Mexican slang? I dont think so. when refering to an older sigling yuo usually say "hermano" or "hermana" when refering to a younger sibling you can say "hermanito" or "hermanita". or just "hermano" or "hermana" . Here in Mexico is common to use nicknames for example if someone's name is Jose they most likely to call him "Pepe" ... Guadalupe- > Lupe or Lupita, Rosario- > Chary o Chayo etc. or maybe with some adjective that kind of describe the person , like "Gordo" "Gorda" "Flaco" "Negro" etc. the translation of this adjectives might sound agresive in english, but they are commonly used in a loving and gentle way... of course there are sweeter adjectives.... for example is not uncommon for couple to call eachother "viejo" or "vieja" in the same fashion. having said that "hermanote" sounds to me more like and ajective than a way to refer to an older brother, for me is like there is someone that you feel like your brother and its huge in size, he migth be really tall or even fat... again in a friendly way. (diminutive of their name is also commonly used, usin your name we coul call you "Dianita" or "Diani") Of course those adjectives can be used negatively . hope it helps!!

Dependiendo de quién se lo dijo a quien, lo más seguro es que sea un apodo