'sepaless' originates from New Latin, specifically the word 'sepalum' combined with the English suffix '-less', where 'sepalum' referred to a sepal and '-less' meant 'without'.

'sepaless' was formed in modern botanical English by adding the adjective-forming suffix '-less' to 'sepal' (from New Latin 'sepalum'), yielding the adjective meaning 'without sepals'.

Initially connected directly to the botanical term 'sepal' meaning 'a part of the calyx'; over time the compound has retained the literal meaning 'without sepals' in botanical usage.