Which title belongs either to all the foregoing women; or rather, as the singular number showeth, to Eglah only, last mentioned; who possibly may be so called, because she was his first, and therefore most proper, wife, though her son was born after all the rest before mentioned, and therefore both she and her son are put in the sixth place; the wives being here named only for the sons sakes. See more on 2 Samuel 3:5.
Related Commentaries of 1 Chronicles 3:3
1 Chronicles 3:3
3 The fifth, Shephatiah of Abital: the sixth, Ithream by Eglah his wife.