Bhakti, literally means "attachment, participation, fondness for, homage, faith, love, devotion, worship, piety", in ancient texts such as which ancient Sanskrit text embedded in the Yajurveda, that is listed as number 14 in the Muktika canon of 108 Upanishads?
Bhakti:  In ancient texts such as the "Shvetashvatara Upanishad", the term simply means participation, devotion and love for any endeavor, while in the "Bhagavad Gita", it connotes one of the possible paths of spirituality and towards moksha, as in "bhakti marga". Shvetashvatara Upanishad: The Shvetashvatara Upanishad (Sanskrit:श्वेताश्वतरोपनिशद or श्वेताश्वतर उपनिषद् IAST "Śvetāśvataropaniṣad ") is an ancient Sanskrit text embedded in the Yajurveda.
Shvetashvatara Upanishad