Abstract

Abstract is synonymous with abstraction and conceptual.

Science
In science, the term abstract refers to objects that are hypothetical or unreal. That which is abstract cannot be an object. If one visualises an abstract object, it will not have location. One cannot establish a distance between the image in one's brain and a real object.

All concepts are abstract, and all that is abstract is conceptual. Therefore in science one cannot refer to an "abstract object." One also should not refer to an "abstract thought," since this may insinuate to the listener that there is an object of reference that cannot be imagined.