Valmiki Ramayana Ayodhya Kanda Sarga 97 Shloka 25

सुमहाकायः huge, शत्रुञ्जयः named Satrunjaya, धीमतः of the sagacious, तातस्य father's, सः that, वृद्धः aged, नागः elephant, एषः here it is, वाहिनीमुखे at the head of the army, कम्पते moving about.

There is that huge and aged elephant named Satrunjaya which belogns to our sagacious father proceeding at the head of the army.