Shakti is one of the names of the wife of Shiva (see Hindu pantheon). It it understood that her consciousness, or energy, is already flowing through all beings in the form of prana, or chi - and that this energy is the goddess herself. People who worship Shakti are referred to as shakta.
The term Shakti is derived from the Sanskrit root shak sometimes translated as 'potency', 'to be able', 'to do' 'power', or 'potential'.
What then is Shakti, and how does it come about that there is some principle of unconsciousness in things, a fact which cannot be denied. Shakti comes from the root "shak," "to be able," "to have power". It may be applied to any form of activity. The power to see is visual Shakti, the power to burn is Shakti of fire, and so forth. These are all forms of activity which are ultimately reducible to the Primordial Shakti (Adya Shakti) whence every other form of Power proceeds.
Arthur Avalon Shakti and Shakta Chap.7