4 occurrences in 4 dictionaries
Reference: Matred
Fausets
Hastings
The mother-in-law (?) of Hadar (Gn.) or Hadad (Ch.), one of the kings of Edom, Ge 36:39 = 1Ch 1:50. In Gn. the Septuagint and Pesh. make Matred the son not the daughter of Me-zahab (wh. see).