'auricularly' originates from Latin, specifically the word 'auricularis', where 'auricula' meant 'little ear' and 'auris' meant 'ear'.

'auricularis' passed into Late Latin and then into Middle English as 'auricular'; the adverb 'auricularly' was formed in English by adding the adverbial suffix '-ly'.

Initially it referred specifically to things relating to the ear (anatomical or liturgical). Over time it also acquired the sense 'by the ear' (aurally) and, in liturgical contexts, 'in a private/secret manner'.