Bhakti-rasāmṛta-sindhu .1.366
tatra veṇuḥ –
[tatra venuh –]
pāvikākhyo bhaved veṇur dvādaśāṅguler dairghya-bhāk ||366||
[paavikaakhyo bhaved venur dvaadashaanguler dairghya-bhaak ||366||]
Blended reading (Sanskrit + English inline)
tatra veṇuḥ –
pāvikākhyo bhaved veṇur dvādaśāṅguler dairghya-bhāk ||366||
The flute which is twelve fingers long [Note: One finger is .75 inches. Thus, the veṇu is about 9 inches long.] named Pāvika is called veṇu.
Purport
Veṇu is very small, not more than six inches long, with six holes for whistling.
— A.C. Bhaktivedanta Swami Prabhupāda
My note
Source: vedabase.io