MATRED mā’ trĭd (מַטְרֵ֔ד). The mother-in-law (?) of Hadar (Hadad), a king of Edom (Gen 36:39; 1 Chron 1:50). In Genesis the LXX and Peshitta make Matred the son of Mezahab.

International Standard Bible Encyclopedia (1915)

The mother of Mehetabel, wife of Hadar, one of the kings of Edom (Ge 36:39; 1Ch 1:50, "Hadad"). The Septuagint and Peshitta designate Matred as male, i.e. as son of Mezahab instead of daughter.