The affix dhan comes in the sense of 'what stays there' after the word tugra , in the chandas (Vedas).,
This debars यत् ॥ Thus तुग्रि॑यः as त्वमग्रे वृषभस् तुग्रियाणां ॥ Which assumes the form तुग्र्य tugrya also. As आवः शमम् वृषभं तुग्र्यासु (Rig Veda l. 34. 15) Tugrya meaning 'sunk in the waters'. The word तुग्र means 'food, firmament, sacrifice and varishtha'.,