'uncounted' originates from English, combining the negative prefix 'un-' with the past participle 'counted', where 'un-' meant 'not' and 'count' meant 'to reckon or compute.'

'count' comes from Old French 'conter' (to count, tell) and ultimately from Latin 'computare' ('com-' together + 'putare' to reckon); 'counted' developed as the past participle in Middle English, and the negated form 'uncounted' arose by prefixing 'un-'.

Initially it simply meant 'not reckoned or not included in a count'; over time it also developed the additional common sense of 'too many to be counted' (i.e. innumerable).