The Greek noun anepsios (ἀνεψιός) refers to a cousin or near relative — a first cousin in classical usage. It appears once in the New Testament in Colossians 4:10, where Mark (John Mark) is identified as the cousin of Barnabas. This single occurrence makes it a hapax legomenon in its New Testament context.
The mention of Mark as Barnabas's cousin (G431) carries significant narrative weight. When Paul refused to take Mark on the second missionary journey (Acts 15:37–39) because Mark had deserted at Perga, a sharp disagreement split Paul and Barnabas — the connection between Barnabas and Mark was not only theological but familial. Barnabas's advocacy for his cousin illustrates how family bonds and gospel mission intersect. Remarkably, Paul later reconciles with Mark: "Get Mark and bring him with you, because he is helpful to me in my ministry" (2 Timothy 4:11). The cousin who caused division eventually became a trusted co-worker — and the author of the Gospel of Mark.