'homosepalous' originates from New Latin, specifically the compound 'homosepalus', where 'homo-' meant 'same' (from Greek 'homós') and 'sepalus' referred to the sepal (a Modern Latin/Neo-Latin formation).

'homosepalous' was formed in modern botanical Latin by combining the Greek prefix 'homo-' and the Neo-Latin element 'sepalus' (from the recently coined word 'sepal' in 19th-century botanical usage), and it entered English technical vocabulary as a descriptive botanical adjective.

Initially it was coined to mean 'having sepals that are the same', and over time it has retained this technical botanical meaning without major change.