Etymology::; The name Vishnu has come from the root ‘vish’ meaning to enter, to pervade and the suffix ‘nu’, translating to approximately “the all pervading one”. The early commentator on the Vedas, Yaska, in his Nirukta, defines Vishnu as Vishnu vishateh; one who enters everything; and ‘yad vishito bhavati tad vishnurbhavati’; that which is free from bondages is Vishnu. Adi Shankara in his commentary on vishnusahasranama states derivation from’vis’, with a meaning”present everywhere”. (As he pervades everything vivesti, he is called Vishnu).
Amarakosha or Namalinganushasanam is a Thesaurus in Sanskrit written by Amarasimha, who was one of the nine gems at the court of Vikramaditya. The following subhashita says about this: