A Sanskrit term that means intense devotion expressed by action (service). A person who practices bhakti is called bhakta.
Bhakti literally means "attachment, participation, devotion to, fondness for, homage, faith or love, worship, piety to (as a religious principle or means of salvation)". Bhakti, in Hinduism, refers to devotion and the love of a personal god or a representational god by a devotee. In ancient texts such as the Shvetashvatara Upanishad, the term simply means participation in, devotion and love for any endeavor, or it refers to one of the possible paths of spirituality and moksha as in bhakti marga mentioned in the Bhagavad Gita. The term also refers to a movement that arose between the 7th century and 10th century CE in India, focussed on the gods Vishnu and Shiva, possibly in response to the arrival of Islam in India.
The Bhakti movement reached North India in the Delhi Sultanate and grew throughout the Mughal era evolving the characteristics of Hinduism as the religion of the general population as dhimmi, under the Islamic rulers in parts of the Indian subcontinent. Bhakti-like movements also spread to other Indian religions during this period, and it influenced the interaction between Christianity and Hinduism in the modern era.
The term bhakti, in modern era, is used to refer to any tradition of Hindu devotionalism, including Shaivism ,Vaishnavism or Shaktism. Bhakti movement rose in importance during the medieval history of Hinduism, starting with Southern India with the Vaisnava Alvars and Shaiva Nayanars, growing rapidly therefrom with the spread bhakti poetry and devotion throughout India by the 12th-18th century CE. The Bhagavata Purana is a text associated with the Bhakti movement which elaborates the concept of bhakti as found in the Bhagavad Gita.
Along with Hinduism, nirguni Bhakti (devotion to the divine without attributes) is found in Sikhism.
Example video: Ram Dass and Jack Kornfield discuss the connections between Buddhism and bhakti yoga.
Example via www.mindpodnetwork.com: Bhakti