This verse lists the names of five of the twelve sons of Ishmael, Abraham's son through Hagar, Sarah's handmaid. In Genesis, genealogies often serve to:

Document lineage and inheritance: This list establishes Ishmael's descendants, contributing to the overall narrative of Abraham's family and the distribution of his blessings.
Indicate tribal origins: The names are generally believed to represent tribal groups that descended from Ishmael. These tribes would have been significant in the region of the Arabian Peninsula.
Fulfill prophecy: God promised Abraham that Ishmael would become a great nation (Genesis 17:20). The listing of his sons and their descendants suggests the fulfillment of this promise.
Provide a historical context: While not a complete historical record, the genealogy offers insights into the population and political landscape of the ancient Near East.

In short, the verse signifies that Hadad, Tema, Jetur, Naphish, and Kedemah were important descendants of Ishmael, likely representing the origin or leaders of distinct tribes associated with him.

While the meaning of each individual name is not definitively known, scholars have proposed possible etymologies and connections to geographical locations and later Arabian tribes. However, the primary significance of the verse is to establish their place within the lineage of Abraham and the broader narrative of Genesis.