Meaning of the Sanskrit Word: drastuh

  drastuh—of the seer    SB 2.5.17, SB 2.9.1, SB 3.7.11, SB 3.31.45-46
  drastuh—of the speaker    SB 3.26.33
  drastuh—of Him who is the seer of everything    SB 5.19.12
  drastuh—of the Supersoul, who witnesses everyone’s activities    SB 9.24.57

Can't find any compound Sanskrit words containing drastuh.