Direct answer: what do you call your brother's son?
Your brother's son is called your nephew. This is the standard English term for the child of your sibling, regardless of whether your brother is your full brother or half-brother. If the boy's parents are not married to each other and you share only one parent with him, he may be referred to as your half-nephew. In everyday usage, "nephew" covers sons and, by extension, daughters of your brothers (nieces). The relationship flows one generation below you and sits within the broader family category of second-degree relatives.
Definition of nephew and related terms
A nephew is the son of your sibling, which includes full siblings, half-siblings, and stepsiblings depending on family structure. Kinship terminology can vary slightly across languages and cultures, but in English the term applies to male children; for female children, the term is niece. Considered a first collateral relative, a nephew lies one generation below you in the family tree. The gender-neutral term "nibling" is sometimes used in scholarly contexts, though nephew and niece remain the most common everyday labels.
Full brother vs half-brother distinctions
Full brother relationship
When you and your brother share both biological parents, his son is your full nephew. This means you and your nephew share approximately 25% of DNA on average, making him a first-degree relative within the descending generation. You are his paternal uncle (or maternal uncle, depending on which side you share), and he is your legal as well as biological nephew for inheritance and guardianship contexts.
Half-brother relationship
If you and your brother share only one biological parent, he is your half-brother, and his son is commonly called your half-nephew. The half-nephew shares roughly half the DNA you would share with a nephew from a full brother, which is about 12.5% on average. In common usage, many people still refer to him simply as nephew, but half-nephew can clarify the more precise biological connection.
Relationship overview and key facts
Understanding the label for your brother's son is useful for family records, legal documents, and clear communication. The term nephew is widely recognized, stable across cultures in English, and unlikely to change. Below is a concise reference table capturing core attributes and typical DNA shares where relevant.
| Attribute | Verified Detail | Source type |
|---|---|---|
| Standard term | Nephew | Dictionaries, kinship terminology |
| Gender-specific term (male) | Nephew | Lexical reference |
| Gender-specific term (female) | Niece | Lexical reference |
| Relationship to nephew | Uncle or aunt | Kinship systems |
| Approximate DNA share (full nephew) | About 25% | Genetics references |
| Approximate DNA share (half-nephew) | About 12.5% | Genetics references |
| Generational position | One generation below you | Kinship structure |
| Legal relevance | Inheritance and guardianship | Legal frameworks |
Cultural and linguistic variations
While English uses nephew broadly for sons and nieces for daughters of siblings, some languages make finer distinctions between maternal and paternal sides. In English contexts, you might also hear uncle or aunt used for the parents of your nephew, but your direct label remains nephew. The term carries no inherent age implication; a nephew can be a toddler, teenager, or adult. In extended family discussions, clarifying full versus half can aid accuracy without changing the core relationship label.
Practical guidance for usage and documentation
In everyday speech, saying "nephew" is clear and widely understood. For formal situations such as legal forms, medical histories, or family trees, specify full nephew or half-nephew if the distinction matters. When introducing your brother's son, you might say "my nephew" or use the child's name, depending on context. Remember that inclusive terms like "nibling" exist but are uncommon in daily conversation. Using consistent language helps avoid confusion, especially in multi-family gatherings or professional settings.