Meonothai was the father of Ophrah, and Seraiah was the father of Joab, the father of those living in Ge-harashim, which was given this name because its people were craftsmen.
We may observe in these verses, 1. That here is a whole family of craftsmen, handicraft tradesmen, that applied themselves to all sorts of manufactures, in which they were ingenious and industrious above their neighbours, Ch1 4:14. There was a valley where they lived which was, from them, called the valley of craftsmen. Those that are craftsmen are not therefore to be looked upon as mean men.
Commenting on 1 Chronicles 4:11-23
And Meonothai,.... Another son of Othniel: begat Ophrah; and Seraiah, the brother of Othniel, begat Joab; not David's general, but another of the same name, who lived long before him, see Ch1 2:54. the father of the valley of Charashim: of the inhabitants of the valley, or the prince of them, called the valley of craftsmen, Neh 11:35 the reason of which is here given...
Joab, the father of the valley of Carashim--literally, "the father of the inhabitants of the valley"--"the valley of craftsmen," as the word denotes. They dwelt together, according to a custom which, independently of any law, extensively prevails in Eastern countries for persons of the same trade to inhabit the same street or the same quarter, and to follow the same occupation from father to son, through many generations.