Jamieson, Fausset and Brown on Genesis 36:2-3

2-3. Esau took his wives of the daughters of Canaan--There were three, mentioned under different names; for it is evident that Bashemath is the same as Mahalath (Ge 28:9), since they both stand in the relation of daughter to Ishmael and sister to Nebajoth; and hence it may be inferred that Adah is the same as Judith, Aholibamah as Bathsemath (Ge 26:34). It was not unusual for women, in that early age, to have two names, as Sarai was also Iscah [Ge 11:29]; and this is the more probable in the case of Esau's wives, who of course would have to take new names when they went from Canaan to settle in mount Seir.