Everyone that enters a Śiva temple cannot fail to see the image of Nandi, the reclining bull. In iconography, Nandi or Nandikeśvara is depicted in two forms as vṛṣabha or reclining bull and as Adhikāra Nandi, an image resembling that of Śiva. In this aspect , the two back hands hold the paraśu (battle axe) and the mṛga (antelope) and the two front hands are folded on the chest in the añjali (obeisance) pose. In all other respects, the characte-ristics of the image are identical with those of Śiva.
Since he is the chief of the gaṇas (retinues) of Śiva, exercising his authority (adhikāra) over them, he is christened ‘Adhikāra Nandi.’ He is also called Nandīśvara or Nandikeśvara.
As regards the origin of this deity, there are three different accounts available in Hindu mythology. Desirous of a son, a sage Sālaṅkāyana by name, propitiated Viṣṇu, who granted his wish by producing a boy exactly resembling Śiva, from the right side of his body. He was named Nandikeśvara. According to another account, a sage called Nandi obtained the status of a god and the headship of the gaṇas of Śiva by propitiating him. A third account depicts him as emerging from the yāgaśālā (sacrificial shed) of the blind sage Śilāda, in the form of an young lad resembling Śiva, thus bringing ‘nandi’ or joy to him. Śilāda adopted him as his son.
Adhikāra Nandi took a prominent part in the destruction of Dakṣa’s sacrifice.
He is more often represented as a bull and also described as the vāhana (mount) of Śiva.
See also NANDI.