Sauti said: Jara, means “waste" Karu means “huge." The body of this Rishi was huge, but he reduced it by severe penances. O Brahmana, because he thus reduced his body, he was called Jaratkaru. The sister of Vasuki was called Jaratkaru for the same reason.
सौतिरुवाच जरेति क्षयमाहुर्वै दारुणं कारुसंज्ञितम्। शरीरं कारु तस्यासीत्तत्स धीमाञ्च्छनैः शनैः॥ क्षपयामास तीव्रण तपसेत्यत उच्यते। जरत्कारुरिति ब्रह्मन्वासुकेर्भगिनी तथा॥