"it exhibits polarity when presented to a magnetic needle"

• the relative orientation of poles; the direction of a magnetic or electric field

  "the magnetic field peaks in strength immediately after switching polarity"

• the state of having two opposite or contradictory tendencies, opinions, or aspects

  "the polarity between male and female"

• the tendency of living organisms or parts to develop with distinct anterior and posterior (or uppermost and lowermost) ends, or to grow or orientate in a particular direction

  "the sponge, possessing an axis of polarity, carries an incurrent siphon at one end and an excurrent siphon at the other"