'aucht' originates from Scots, ultimately from Old English 'eahta' and Proto-Germanic '*ahtōu', where the root '*aht-' meant 'eight'.

'aucht' changed from Old English 'eahta' (and related Old Norse forms such as 'átt'), passed through Middle English dialectal forms, and became the modern Scots form 'aucht'.

Initially it meant 'the number eight'; over time this core meaning has remained essentially the same.