Traditionally Ma Parvati is regarded as Shakti because Shiva represents the Force aspect of the One Satchidananda, just as Brahma represents the Sat aspect and Ma Saraswati is the Creative Shakti, Vishnu is the Chit aspect and Ma Lakshmi is the prema Shakti, Krishna is the Ananda aspect and Ma Radha is the Hladini Shakti. Each consort of the gods is his shakti in its own right.
But there is the original Shakti from whom all other powers derive. She is the Adya Shakti, the Shakti of the Parameshwara, the Supreme Lord who is Sacchidananda himself. Sacchidananda is the supreme Purusha beyond the gods who are aspects and powers derived from Him.
Affectionately,
Alok Da
