A set of assumptions, ideas and standards that form a viewpoint from which philosophical, religious and other ideas may be evaluated.
A set of axes which enable an observer to measure the position and motion of all bodies in some system relative to the reference frame.
The theory of a particular philosopher or school of thought concerning the fundamental types of entity in the universe.
A logical system involving theory of classes, developed by Stanislaw Lesniewski (1886-1939).
A structure of concepts or entities within a domain, organized by relationships; a system model.
The branch of metaphysics that addresses the nature or essential characteristics of being and of things that exist; the study of being qua being.
In a subject view, or a world view, the set of conceptual or material things or classes of things that are recognised as existing, or are assumed to exist in context, and their interrelations; in a body of theory, the ontology comprises the domain of discourse, the things that are defined as existing, together with whatever emerges from their mutual implications.