Final answer:
Set-theoretical difference, or relative complement, refers to the elements in one set that are not in another, which is a concept from mathematics, specifically set theory.
Step-by-step explanation:
The concept in question relates to sets and their properties within the realm of mathematics. When discussing the relative complement or the set-theoretical difference, we refer to the elements that belong to one set, say Set A, but not to another, say Set B, denoted as A \ B. It is a fundamental aspect of set theory, a branch of mathematical logic that deals with the nature and relations of sets, collections of objects considered as objects in their own right.
A practical example involves two sets of numbers, where Set A might contain the numbers {1, 2, 3, 4, 5} and Set B contains {3, 4, 5, 6, 7}. The relative complement of Set B in Set A, A \ B, would be {1, 2}, because those are the numbers that are in Set A but not in Set B.
It's important to distinguish between this and wider mathematical concepts such as classical relativity, which refers to the study of relative velocities in non-relativistic physics, or vector components and direction, which are terms used in the field of physics.