'apportionate' originates from English, formed by adding the suffix '-ate' to the verb 'apportion', where 'apportion' comes from Old French 'apportioner' (from Latin elements related to 'portio' meaning 'a part').

'apportionate' was formed in English by morphological extension of 'apportion' (Old French 'apportioner'), which itself derives from Latin roots such as 'portio' ('portion'); the modern English adjective/verb 'apportionate' developed as an analogical formation alongside 'apportion' and 'apportionment'.

Initially the root idea was 'to divide into portions' (from Latin 'portio' meaning 'a part'), and over time the English formations have retained this basic meaning of dividing or making proportionate.