Meaning of the Sanskrit Word: sisyam

  sisyam—unto his disciple    SB 8.19.29
  sisyam—unto such a disciple    SB 8.20.14
  sisyam—unto his disciple, Vrsaparva    SB 9.18.27
  sisyam—because of his being a disciple    SB 8.15.34

Can't find any compound Sanskrit words containing sisyam.