Skt., dasa: ten
maha: great
vidya: transcendental wisdom
Mahavidya is a collective name for ten major goddesses of the Indian pantheon, all of whom are regarded as aspects of Shakti.
Other names for this group of goddesses are dasa mahavidya and nitya ("eternal", "unchanging"), the latter one specifically indicating that these mothers of life and death are eternally present and active.
Here a list of the individual deities/names:
Note:
Among the numerous texts and schools that follow/promote the teachings of Shakta and
Tantra, sometimes the list of names differs slightly from the most common one given here.
The probably best book about these ten goddesses is David Kinsley's
Tantric Visions of the Divine Feminine.