Nandi (Sanskrit: नन्दि), also known as Nandikeshvara or Nandideva, is the bull vahana (mount) of the Hindu god Shiva. Within the Shaiva tradition, he is regarded as the constant companion of Shiva and a central figure in the iconography associated with the deity.
In addition to serving as the mount, Nandi is venerated as the guardian deity of Kailash, the mountain abode of Shiva. He is portrayed as a devoted attendant whose presence signifies fidelity, strength, and watchfulness in the service of his master.
Nandi occupies a prominent place in temple architecture and ritual practice. Almost all Shiva temples display a stone image of a seated Nandi, generally positioned facing the main shrine so that his gaze is directed towards the deity within the sanctum. Devotees commonly offer reverence to Nandi before approaching the shrine of Shiva, and the bull's image is considered an essential element of Shaiva temple layouts.
Adapted from the English Wikipedia article on Nandi (Hinduism).