In this paper we present and discuss a meta-ontological architecture for ontologies which centers on
abstract core ontologies
(ACOs). An ACO is the most abstract part of a foundational ontology. It is useful for an ontologically founded description of ontologies themselves, therefore ACOs are lifted to the meta-level. We propose a three-layered meta-ontological architecture which distinguishes an object level comprising foundational, generic or domain-specific ontologies, a meta-level with abstract core ontologies, and a meta-meta-level employing
abstract top ontologies
for the formalization of the underlying levels. Moreover, two axiomatic fragments for ACOs are provided, one of which is applied to
formal concept lattices
. This demonstrates the use of ACOs for the ontological foundation of representation formalisms and illustrates advantages in comparison to the usual direct formal reduction to set theory. Finally, related work with respect to the architecture is briefly discussed.