The term 'seldom-overseen' is a compound word formed from 'seldom' and 'overseen'. 'Seldom' originates from Old English 'seldan', meaning 'rarely', and 'overseen' is the past participle of 'oversee', which comes from Middle English 'overseon', meaning 'to look over'.

The word 'seldom' evolved from Old English 'seldan', while 'overseen' transformed from Middle English 'overseon'. The combination of these words into 'seldom-overseen' is a modern English formation.

The meaning of 'seldom' as 'rarely' and 'overseen' as 'supervised' has remained consistent, leading to the straightforward meaning of 'seldom-overseen' as 'rarely supervised'.