Shaktism is a Sanskrit term and means “Doctrine of the Goddess”. It is that aspect of Hinduism that focuses upon worship of Shakti (feminine power) or Devi, who is the Divine Mother. In Hinduism, the Great Divine Mother is regarded as the symbol of motherhood and power/energy. In Shaktism goddess worship, in all her forms is the practice. Shaktism regards Mahadevi as the Great Goddess. Here Shakti is the dynamic feminine aspect of the Supreme Divine.
Deities of Shaktism possess the very energy of existence, as Shakti is active, creative energy and each Goddess is profiled with her Shakti (power). The Goddess is seen as the personification of all creative energy and the source of all divine and cosmic evolution including all aspects of Nature.
In Hinduism, Adi Shakti is the ultimate Shakti, the final feminine power inherent in all creations. There are supposed to be a group of seven or eight mother goddesses, called the Matrikas. They are Brahmani, Vaishanvi, Maheshwari, Indrani, Kumari, Varahi and Chumnda and/or Narasimhi. The matrikas are considered Shaktis of the most important gods like Brahma, Vishnu, Shiva, Indra, Skanda or Kumara, Yama and Narsimha. Shakti is seen as a sign of protection of the country, the punisher of evil people, the curer of diseases and the one who gives happiness to the village.
The worship of Mother Goddess or Shakti, can be traced back to the Pre-Vedic or Indus Valley Civilisation. Devisukta of the Rig Veda is the primary source of Shakti Cult. In the Rig Veda there is a description of a goddess named 'Aditi'. She is depicted not only as Mother Goddess but also as an emblem of the divine spirit. Some other references of Mother Goddesses are Prithvi (earth), Vac (speech) and Usas (dawn).
Over time when the Puranic gods and goddesses gained prominence, the prominence of the Shakti worship did not ebb. It continued to flourish and the associated myths and the temples associated with this myth remained prime centres of pilgrimage. Needless to say, that in many a case, myths got inter-woven with that of the Puranic deities to co-exist.
To conclude, according to Shiva Purana, Shiva is shava (dead body) without his energy, Shakti. This underlines the significance of the concept of Shakti.