The noun ‘difference’ can be found in two main contexts: that of logic, which will concern us here, and the loaned meaning of social relations of disagreement and dispute. This derived latter sense appears in the following the OED 1844 quote from R. W. Emerson: “Difference of opinion is the one crime which kings never forgive”. The logical concept of ‘difference’ is abstract; the adjective ‘different’ is conceived as the opposite of ‘similar’ and the ‘same’. ‘Difference’ concerns the ability to compare and separate and notice the way individual things or events are identical, similar, or at variance. Here again, as in the case of ‘similarity’, there is no simple way to denote ‘difference’. Dictionaries specify several meanings of types of differences. One is the quality of being unlike or dissimilar, as in the following example:

1. There are many differences between jazz and rock.