After Madanabhasma (the burning of Madana), Mahādeva (Mahadeva) disappeared and Pārvatī (Parvati; daughter of Parvata; that is the mountain Himalaya) Umā(Uma) started tapasyā (tapasya; ascetic practice) for him. She made an altar at the very place where Rudra-Śiva burned Madana, and started her tapasyā, sitting there. During this hard ascetic practice, she lived only on tree- leaves. Gradually, she abstained from eating green leaves, and used to take only dry leaves. Finally, she refused to take any kind of leaves, and since she left leaf-eating altogether, she came to be known as Aparṇā (Aparna).

In the Saubhāgyabhāskara ṭīkā (Saubhagyabhaskara tika; Commentary by Saubhagyabhaskara) of Lalitā Sahasranāma (Lalita Sahasranama; Thousand names of Lalita), a new meaning of ‘Aparṇā’ is offered, saying that — the goddess who does not keep herself indebted to her devotees, is Aparṇā. In this context, the commentator has cited a śloka (sloka; verse) from Devīstava (Devistava; Hymn to Goddess)), and said, — I have meditated on your name for so long, and yet you have not appeared before me, to pay the debt of that meditation. Still your name is Aparṇā, and the gross meaning of that name become a burden upon me —
ṛṇamiṣṭamadatvaiva tvannāma japato mama.
śive kathamaparṇeti rūḍhirbhārāyate mama.
In Kālikāpurāṇa (Kalikapurana) and Brāhmāṇḍapurāṇa (Brahmandapurana), however, the issue of abstination from leaf-eating has been mentioned in the context of the tapasyā of Umā.