Appajim belonged to Jerahmeel's branch of the tribe of Judah and is known from the genealogy in 1 Chronicles. As the son of Nadab and father of Ishi, he formed an important link in this family line. Because his brother Seled died childless, it was Appajim who alone continued Nadab's branch. The genealogy he is part of was recorded to keep track of Judah's family lines and ensure documentation of tribal affiliation and inheritance rights in Israel's history.
Appajim is recorded as the son of Nadab and brother of Seled in the genealogy of Jerahmeel's descendants. Seled died without children, while Appajim carried on the family line.
Appajim's lineage is part of the larger genealogy of the tribe of Judah, which documents Israel's tribal history from Judah through Jerahmeel's branch.