Meaning of the Sanskrit Word: tamasam

  tamasam—in the mode of ignorance    Bg 17.13, Bg 18.25, Bg 18.39
  tamasam—in the mode of darkness    Bg 17.19, Bg 17.22, Bg 18.22
  tamasam—material elements    SB 5.17.22, SB 5.17.23, SB 5.17.22-23

Can't find any compound Sanskrit words containing tamasam.