'Gūfu' refers specifically to the husband of one's paternal aunt — that is, the man married to your father's sister. The first character 姑 (gū) means 'paternal aunt', while 父 (fù) means 'father' or 'male elder'; together, they form a kinship term indicating a familial relationship by marriage, not blood. Unlike English, which often uses generic terms like 'uncle', Chinese distinguishes relatives precisely by lineage (paternal vs. maternal) and marital connection.

This term is used in formal family settings, genealogical discussions, or when introducing relatives. It carries respectful connotation and is typically addressed with titles like 'Gūfu' or 'Gūfu hǎo' (Hello, Uncle). It is not used for maternal aunts’ husbands — that role is filled by 'Yífu'. Understanding such distinctions helps learners navigate Chinese family conversations accurately and respectfully.