the mind > mental capacity > perception or cognition > faculty of ideation > idea, notion, or concept > [adverb] (5)
in idea: in conception or imagination; in mind, in thought, often as opposed to reality; †also with possessive adjective.
In conception; conceptually.
In a conceptual manner; in terms of concepts.
In a way characteristic of conceptualism or conceptualists; conceptually, in terms of concepts.