saidar

In The Wheel of Time, a female half of One Power, from one and only True Source. Just as with saidin, wielding it can produce strange effect that appears as magic to non-channelers.

Wielding saidar is described as 'surrendering' to the One Power; channeler is to embrace the flow and surrender to it, to guide the roaring river like riverbank guides river. This is obviously different from saidin, and indeed, if women tries to wield saidar in the fashion men wield saidin (seizing it), she will only find saidar fights back, the harder you try the stronger it fights back. If man, on the other hand, tried to surrender to saidin he would surely be swept away.

Unlike saidin, saidar has no problems with taint and therefore only danger on using it is power addiction, that could lead into over-drawing OP and burning yourself (and village around you) out.

P.S. It is rumored that the difference between saidin and saidar may not be that huge. While neither can actually 'see' the flows of other side (note that saidar-wielder can't 'see' even saidar before she's trained to!), they can sense it channeled. Mostly this idea is to annoy Robert Jordan, propably, though. Verin Mathwin Sedai's side comment might have something to do with it though.

Wilders like Nynaeve al'Meara, women who enter Tar Valon after they discovered how to channel saidar on their own, do not touch saidar in the same way that others do. Often their method of channeling somehow relates to extreme emotion or childhood habits; for instance, Nynaeve's anger. It is because of this that Nynaeve can only channel when she gets angry (or at least this is true in the beginning of The Wheel of Time). Wilders can be taught to touch the True Source in the traditional and most effective way, especially through incidents where they are forced into channeling in an instant where their block would usually prevent them. Once the block has been passed once, it is gone for the rest of a channeler's life.

The traditional metaphor used by Aes Sedai to teach submission is the flower, accepting the sun's (saidar's) energy and channeling it. Men who can touch saidin feel a tingling sensation whenever a woman channels saidar. However, women have no way of detecting a man's channeling, though Moghedien suggested that it might be possible through a weave. The weave that she explained was only a diversion, but there is a very real possibility that the real weave exists.