Meaning of the Sanskrit Word: tvastram

  tvastram—the son of Tvasta    SB 6.7.25, SB 6.9.40
  tvastram—the demon Vrtra (son of Tvasta)    SB 3.19.25
  tvastram—to the son of Tvasta    SB 6.7.26
  tvastram—the demon Vrtrasura, son of Tvasta    SB 6.9.44
  tvastram—meant for the demigod known as Tvasta    SB 6.14.27
  tvastram—performed by Tvasta    SB 8.11.35

Can't find any compound Sanskrit words containing tvastram.