A particular, minute unit of mass, defined differently for different substances, but so that varying substances of the same general type have the property that one international unit of the one has the same effect on the human body as one international unit of the other.
User Defined Definitions
"any division of quantity accepted as a standard of measurement or exchange"
"an individual or group or structure or other entity regarded as a structural or functional constituent of a whole"
"an organization regarded as part of a larger social group"
"a single undivided whole"
"a single undivided natural thing occurring in the composition of something else"
"an assemblage of parts that is regarded as a single entity"