सिंहनादं विनद्योच्चैः शङ्खं दध्मौ प्रतापवान् ॥ १२ ॥
śaṅkhaṁ dadhmau pratāpavān
tasya — his; sañjanayan — increasing; harṣam — cheerfulness; kuru-vṛddhaḥ — the grandsire of the Kuru dynasty (Bhīṣma); pitāmahaḥ — the grandfather; siṁha-nādam — roaring sound, like that of a lion; vinadya — vibrating; uccaiḥ — very loudly; śaṅkham — conchshell; dadhmau — blew; pratāpa-vān — the valiant.
Then Bhīṣma, the great valiant grandsire of the Kuru dynasty, the grandfather of the fighters, blew his conchshell very loudly, making a sound like the roar of a lion, giving Duryodhana joy.
The grandsire of the Kuru dynasty could understand the inner meaning of the heart of his grandson Duryodhana, and out of his natural compassion for him he tried to cheer him by blowing his conchshell very loudly, befitting his position as a lion. Indirectly, by the symbolism of the conchshell, he informed his depressed grandson Duryodhana that he had no chance of victory in the battle, because the Supreme Lord Kṛṣṇa was on the other side. But still, it was his duty to conduct the fight, and no pains would be spared in that connection.