Bhashya
तथा भू प्रपद्ये इति त्रीँल्लोकान्भूरादीन्प्रपद्ये इति तदवोचम् ॥
In plain words
Similarly, by the phrase 'I take refuge in bhuh,' I expressed: 'I take refuge in the three worlds, beginning with the terrestrial realm.'
Close to the Sanskrit
Likewise, saying 'I take refuge in bhuh', I spoke: 'I take refuge in the three worlds beginning with bhuh.'