Uncle (from avunculus the diminutive of avus "grandfather") is a male family relationship or kinship within an extended or immediate family. Uncles are second-degree relatives and share 25% genetic overlap when they are the full brother of one of the biological parents. An uncle is the brother of a parent. A half-uncle is the half-brother of one's parent. Uncle-in-law can refer to the husband of one's aunt or uncle of one's spouse.
In some cultures and families, children may refer to the cousins of their parents as aunt or uncle due to the age difference. It is also a title of respect for elders (for example older cousins, neighbours, acquaintances, close family friends, and even sometimes total strangers). Using the term in this way is a form of fictive kinship.
The female counterpart of an uncle is an aunt ("auntie" when used as a term of familiarity or respect), and the reciprocal relationship is that of a nephew or niece.
A great-uncle/granduncle/grand-uncle is the brother of one's grandparent.
Albanian, Slavic and PersianIn some cultures, like Albanian, Slavic, or Persian, no single inclusive term describing both a person's kinship to their parental male sibling or parental male in-law exists. Instead, there are specific terms describing a person's kinship to their mother's brother ("dajë" in Albanian language, "daiyee" in Persian, "wuj" (diminutive: "wujek") in Polish) or a person's kinship to their father's brother ("xhajë" in Albanian, "amou" in Persian, "stryj" (diminutive: "stryjek") in Polish). An analogous differentiation exists using separate terms to describe a person's kinship to their mother's female sibling, ("teze" in Albanian, "khaleh" in Persian, "ciotka" (diminutive: "ciocia") in Polish), and a person's kinship to their father's female sibling, ("hallë" in Albanian, "ammeh" in Persian, "stryjna" (diminutive: "stryjenka") in Polish).
Furthermore, in Persian culture the terms used to describe a person's kinship to their maternal or paternal in-laws bear clear and unambiguous descriptions of that relationship, differentiating the parental in-laws from blood-relatives. For example, there is a specific term describing a person's kinship to the spouse of their paternal uncle (i.e. "zan-amou", literally 'wife-of-' amou). This clarifies that kinship is to the spouse of the person's paternal male sibling, as opposed to a blood-relationship.
IrishUncles and aunts are considered important in modern Irish culture and are usually chosen to be godfather or godmother of children during Catholic baptism. A young Irish person might seek the counsel of their favorite aunt or uncle before making an important decision, and the opinion of the respective aunt or uncle is treated seriously.
South AsianIn India, unambiguous names are used for various uncles such as father’s brother chacha (or kaka). If the brother of your father is elder than your father then he is called Tauji ( or bapuji). Your mother’s brother is called Mama. Your paternal aunt’s husband is called Fufa (or Fuva) and your maternal aunt’s husband is called Mausa (or Masa) in Hindi (or Gujarati).
Likewise, in neighbouring Bangladesh, mother's brother is also Mama as well father's brother as Chacha. A paternal aunt's husband is Phupha and maternal aunt's husband is Khalu.
Uncles in popular culture
Due to the loving image of an old but wise and friendly uncle in many cultures the word has been used as a loving nickname for many people. In Tibetan mythology Akhu Tönpa (Uncle Tompa) is a familiar and well-beloved figure. The American national personification Uncle Sam serves as an allegorical fatherly figure to many Americans. Various children's TV hosts have used uncle as their nickname, including Walt Disney (Uncle Walt), Bob Davidse (Nonkel Bob, literally Uncle Bob), Edwin Rutten (who hosted a children's show named De Show van Ome Willem (The Show of Uncle Willem). The Dutch poet Ome Ko also used uncle as part of his pseudonym.
Rich, wise or otherwise eccentric uncles are also popular in works of fiction.