noun
willpower; power of faith; power of prayer
An older or more religious-sounding use referring to the power of concentrated thought, belief, or prayer; in modern everyday Japanese, 精神力 or 信念 is often more ordinary for simple 'willpower'.
彼女は念力をこめて、父の回復を祈った。
She prayed for her father's recovery with all the force of her faith.
noun
The common modern sense: paranormal power used to move or affect things by mental force.
映画では、少女が念力で物を動かす。
In the movie, the girl moves objects with telekinesis.
彼は念力でスプーンを曲げられると言った。
He said he could bend spoons with psychokinesis.