The word "Vlva" (plural "Vlvur") comes from the scandinavian language and means "carrier of magic staff". The term "fjolkunnig" is sometimes used to name them, showing their knowledge of practices known as "seir" (witchcraft, chamanism), "sp" (soothsaying, clairvoyance) and "galdr" (spell, incantation).

Seir is, in norse mythology, an activity Freyja taught to Ases, whose only Odin would have become a master. Seir is mentioned in Gylfaginning and Volusp. Seir was mainly practiced by women called seikona, but there also was seimar (men practicing seir). This magic calls in ergi and it is considered "shameful for a man to practice it perfectly".

Historical and mythological representations show seikona were held in high esteem and believed to possess such powers that even the father of the gods, Odin himself, consulted a Vlva to learn what the future had in store for the gods. This prophecy is transcripted in a poem known as Vlusp ("prophecy of the Vlva").

Vlvur were not considered to be harmless. Goddess Freyja, the most skillful in these arts, was not only a goddess of love, but also a warlike divinity. What Freya performed in Asgard, the world of the gods, the Vlvur tried to perform in Midgard, the world of men. Their weapon  was not the spear, the axe or the sword, but instead they were held to influence battles with different means, and one of them was their powers.

Their disappearance was due to the Roman Catholic Church, which along with civil governments had laws enacted against them.

"If any wicca (witch), wiglaer (wizard), false swearer, morthwyrtha (worshipper of the dead) or any foul contaminated, manifest horcwenan (whore), be anywhere in the land, man shall drive them out. We teach that every priest shall extinguish heathendom and forbid wilweorthunga (fountain worship), licwiglunga (incantations of the dead), hwata (omens), galdra (magic), man worship and the abominations that men exercise in various sorts of witchcraft, and in frithspottum (peace-enclosures) with elms and other trees, and with stones, and with many phantoms."

-- 16th canon law enacted under King Edgar the Peaceful in the 10th century