To differentiate similar things.

The difference between one measurement of time and another; the length of a time interval. / The difference in clock time between two or more different time zones.

(euphemistic, often humorous or pejoratively so except India) Disabled or handicapped.

(set theory) The set that contains all elements belonging to either of given two sets but not to the both; the relative complement of the intersection in the union of given two sets.

(mathematics) The constant added to each element of an arithmetic progression to obtain the next.

(sports) The difference between the number of goals scored and the number of goals conceded, over the duration of a competition.

plural of spot the difference

A difference between the value of a function evaluated at a number, and the value of the same function evaluated at a different number, a fixed distance from the first.

(idiomatic, intransitive) To carry out an action, the result of which is a significant change, or an altered circumstance. / (idiomatic, intransitive) To be of importance; to matter.

(attributive) spot the difference