Charles Ellicott Commentary 1 Chronicles 1:39

"And the sons of Lotan: Hori, and Homam; and Timna was Lotan`s sister." — 1 Chronicles 1:39 (ASV)

And Timna was Lotan’s sister. —This appears to mean that the tribe settled in the town of Timna was akin to the sons of Lotan, but not a subdivision of that tribe. Towns are feminine in Hebrew, and are sometimes called mothers (2 Samuel 20:19), sometimes daughters.