रङ्गनाथ अष्टोत्तर शतनामावली — Word-by-Word Meaning

The 108 names of Lord Ranganatha of Srirangam, Vishnu reclining upon the serpent Adishesha — each recited with “Om” and “namaḥ”, the supreme deity of the Sri Vaishnava tradition.

It is chanted as an archana: each of the 108 names is recited with “Om” (ॐ) before it and “namaḥ” (नमः) after it, while offering a flower or a pinch of kumkum at the deity’s feet for each name. The complete garland of 108 names is offered in one sitting, especially on Thursdays and Ekadashi and during Ekadashi and Vaikuntha Ekadashi.

“Ashtottara-shata” means “a hundred and eight” (108) and “namavali” means “a garland of names”. So it is the sacred list of the 108 names of Ranganatha, each a name of praise and meditation.