the mind > mental capacity > perception or cognition > faculty of ideation > topic, subject-matter > affair, business, concern > [adverb] (4)
In that affair or matter; in that thing, circumstance, or particular.
interrogative. About or concerning what? on what business or occupation? Obsolete.
interrogative and relative = whereabout, adv. n.2. Obsolete.
= therein, adv. 2. Cf. into, prep. 14. Obsolete.