'aposepalous' originates from Greek and New Latin, specifically from the prefix 'apo-' (Greek) meaning 'away from, separate' combined with Neo-Latin 'sepalum' (from which 'sepalous' is formed) meaning 'sepal (a leaf-like part of the calyx)'.

'aposepalous' was formed in botanical Latin by joining the Greek prefix 'apo-' with the Neo-Latin element 'sepalous' (from 'sepalum'), and was adopted into English botanical usage in the late 19th to early 20th century with essentially the same form.

Initially it denoted 'sepals separate from one another,' and over time this technical botanical meaning has remained stable into modern usage.