[ the thumbnail, the claw, is irreparably cracked ]

For me, it is called "Weave". Fine threads of raw magic which blanket my planet. All spells are formed by manipulating this "Weave", and it is my willpower which makes it do what I wish. However, if it is not present, then I cannot cast.

[ is what she would normally say, except this isn't Toril, and the magic yet flows ]

There is more to it than strength of will only, for me. I can know precisely what to do, but if I cannot speak, yet wish to cast spell that requires verbal component, then... poof. Nothing.