'prechosen' is formed from the prefix 'pre-' and the past participle 'chosen'. 'pre-' originates from Latin, specifically the word 'prae', where 'prae-' meant 'before'; 'choose' ultimately comes from Old English 'ceosan'.

'choose' changed from Old English 'ceosan' to Middle English forms (e.g. 'chese', past participle 'chosen'), and the prefix 'pre-' (from Latin 'prae-') was later attached to form the compound adjective 'prechosen' meaning 'chosen beforehand'.

Initially the elements meant 'before' + 'to choose', and combined they have meant 'chosen beforehand' since formation; the core meaning has been largely stable.