One of Śiva’s (Shiva’s) one thousand names. Ananta, in dictionaries, is defined as antahīna (antahina; anta means end, and hīna means without, together, endless). While on one hand, ananta denotes immense expanse without beginning or end, on the other it means that beyond prediction or enumeration and is a signifier for many words. In both senses it may be taken as a name for Śiva-Mahādeva (Mahadeva). The annotator Nīlakaṇṭha, to explain the name Anantarūpa (Anantarupa) has said—
anantaṃ rūpamasya so’nantarūpaḥ.
The great form of Parameśvara (Parameshwara, roughly translated as the Supreme One) without beginning or end that is imagined, the immense expanse of which Arjuna, in Bhagavadgītā (Bhagavadgita), has described as ‘nabhaḥspṛśaṃ dīptamanekavarṇaṃ‘, it is because of that gargantuan frame that Mahādeva, who is also an incarnation of Parameśvara, is renowned as Anantarūpa. Incidentally, we find ‘Anantarūpa’ as one of the many names of Viṣṇu in Viṣṇusahasranāmastotra (Vishnusahasranamastotra). According of brahma thought in Upaniṣadas (Upanishadas), Parameśvara is considered to be without shape or form. By creating the universe, that formless Paramātmā (Paramatma, roughly translated as the Supreme Soul), takes shape, as his true form is embodied by all animate and inanimate beings of the world. The shapeless Parabrahma (or the Supreme brahma) reveals himself by manifesting himself in various forms, and so, the god assuming so many appearances is known as Anantarūpa. It is with this connotation that Anantarūpa has been explained in the Śāṅkarabhāṣya (Shankarabhashya) annotations of the one thousand names of Viṣṇu—
anantāni rūpāṇyasya viśvaprapañcarūpeṇa sthitasyeti anantarūpaḥ.
There may be one other denotation of the word ‘ananta‘—he for whom there is no end or death. Since god is indestructible, he is also known as Anantarūpa.