Having little or no tendency to take a fixed or definite position or direction: thus, a suspended magnetic needle, when rendered astatic, loses its polarity, or tendency to point in a given direction
{s} (Medicine) suffering from astasia (inability to stand due to lack of muscular coordination); unstable
an arrangement of coils used in sensitive electrical instruments; the coils are arranged to give zero resultant external magnetic field when a current passes through them and to have zero electromotive force induced in them by an external magnetic field