'septally' originates from Latin, specifically the word 'septum', where 'sept-' meant 'a fence or partition'.

'septally' was formed from the adjective 'septal' (from Latin 'septum' via New/Scientific Latin) and then took the English adverbial suffix '-ly' to become 'septally'.

Initially related to the noun 'septum' meaning 'partition', it evolved to mean 'relating to or situated at a septum' in modern usage.