Ṛtu (Ritu) is one of the names of God Viṣṇu (Vishnu), included in Viṣṇusahasranāmastotra (Vishnusahasranamastotra; Thousand Names of God Vishnu in the form of a hymn), as described in Anuśāsanaparva (Anusasanaparva) of Mahābhārata (Mahabharata).