the mind > mental capacity > perception or cognition > faculty of ideation > topic, subject-matter > be occupied with a topic [verb (intransitive)] > stick to the point (2)
intransitive. To keep to (a particular topic or subject) when writing or speaking; not to digress from (a particular topic or subject).
‘Let us return to the matter in hand.’ Cf. to return to one's muttons at mutton, n. phrases 3.