In Hindustani music, a pakad is a generally accepted musical phrase (or set of phrases) thought to encapsulate the essence of a particular raga. The pakad contains the melodic theme of the raga, on listening to the pakad a person who knows the raga is usually able to identify it. In many cases, the ragas contain the same swaras (notes), then the pakad also contains information about gayaki or chalan (the way the notes are to be ordered and played/sung). Usually, the pakad is formed from short convolutions of the arohana and avarohana, while in some cases it is quite different from them. The pakad for a particular raga need not be unique, its sole purpose is to clarify what raga it is.
For example, here is a pakad for raga Yaman, a prominent raga from Hindustani Music:
Ni* Re Ga Ma# Pa, Ma# Ga Re Sa.