1) money that is owing and that ought to have been paid (arrears)

2) anything owned by a person, business etc that has money value and that may be sold to pay debts (asset)

3) all the characteristics that belong to an individual and that distinguish her or him from others (individuality)

4) (the belief in) the main theory of Karl Marx (1818 - 1883) that social and political changes are caused by a struggle between social classes and that socialism will eventually replace capitalism (marxism)

5) concerning pantheism ( = (the belief in) the theory that God is in everything and that everything is God) (pantheist)

6) the distance between the highest point of one wave and that of the next (wavelength)