'seldom-viewed' originates from Modern English, specifically the words 'seldom' and 'viewed', where 'seldom' meant 'rarely' and 'viewed' is the past participle of 'view' (to see).

'seldom' comes from Old English 'seldum' meaning 'rarely'; 'viewed' is formed from 'view', which entered English via Old French 'veue' / Latin roots from 'videre' ('to see'). The compound 'seldom-viewed' is a modern English formation combining the adverb 'seldom' with the past participle 'viewed'.

Initially the components meant 'rarely' ('seldom') and 'to see' ('view'); over time the combined form evolved to describe something 'rarely seen' (an adjectival use).