The father (the king) who was equal to the Grandsire, then bestowed a name on that child. As the (fragments of the body of the child) was united by Jara, he was named Jarasandha.
तस्य नामाकरोच्चैव पितामहसम: पिता। जरया संधितो यस्माज्जरासंधो भवत्वयम्॥