'seldom-updated' is a compound word formed from 'seldom' and 'updated'. 'Seldom' originates from Old English 'seldan', meaning 'rarely', and 'updated' is derived from 'update', which comes from the prefix 'up-' meaning 'to a higher position' and 'date', from Latin 'datum', meaning 'given'.

'seldan' transformed into the Middle English 'seldom', and 'update' was formed in the 20th century from 'up-' and 'date'.

Initially, 'seldom' meant 'rarely', and 'update' meant 'to bring up to date'. The compound 'seldom-updated' retains these meanings, indicating something that is rarely brought up to date.