Albert Barnes Commentary 1 Chronicles 2:54

"The sons of Salma: Beth-lehem, and the Netophathites, Atroth-beth-joab, and half of the Manahathites, the Zorites." — 1 Chronicles 2:54 (ASV)

Ataroth, the house of Joab - This is more accurately “Ataroth-beth-Joab,” likely named this way to distinguish it from Ataroth-adar, a city in Benjamin (Joshua 18:13). It is uncertain from which Joab it derived its distinctive name.