Meaning of the Sanskrit Word: nanrtuh

  nanṛtuḥ—began to dance    SB 7.8.36, SB 8.11.41, SB 9.10.41
  nanṛtuḥ—danced    SB 7.10.68, SB 8.4.2
  nanṛtuḥ—very nicely danced on the occasion    SB 8.8.12
  nanṛtuḥ—danced in transcendental bliss    SB 10.3.6

Can't find any compound Sanskrit words containing nanrtuh.