Hage Appa
Hage Appa is a Korean term of endearment and a common phrase used to refer to a grandfather. It is a combination of two words: "Hage" (하계), a common transliteration of "harabeoji" (할아버지) meaning grandfather, and "Appa" (아빠), meaning father.
While "Harabeoji" is the standard and more formal way to say grandfather, "Hage Appa" is more informal and affectionate. Its use implies a close and loving relationship between the speaker and their grandfather. It is most often used by children or grandchildren when directly addressing their grandfather. The "Appa" element adds a familial warmth suggesting that the grandfather is viewed not just as an ancestor, but also as a father figure.
The level of formality of the word sits between the very formal "Harabeoji" and potentially using just the given name followed by "Appa", if that were common in a given family.