What does "meum" mean?

Meum: Lit., mine; that which is mine; -- used in the phrase meum et tuum, or meum and tuum; as, to confound meum and tuum, to fail to distinguish one's own property from that of others; to be dishonest. Ancestors . . . generally esteemed more renowned for ancient family and high courage than for accurately regarding the trifling distinction of meum and tuum. Sir W. Scott.