'digit-based' is a modern compound made from 'digit' + 'based'. 'digit' originates from Latin, specifically the word 'digitus', where 'digitus' meant 'finger' (and by extension a 'numeral' used for counting). 'base' (as used in 'based') comes from Old French/Latin roots related to 'basis' meaning a foundation.

'digit' entered English via Latin 'digitus' (and Medieval/Old French influences) and came to mean both 'finger' and 'numeral' (from finger-counting). 'based' is the adjectival/past-participle form of 'base', which evolved from Old French/Latin terms such as 'basis' and became used in compounds and adjectival phrases in modern English; the compound 'digit-based' is a recent formation (20th century onward) as technical language around digital/numerical systems developed.

Initially, 'digitus' meant 'finger'; over time it also came to mean 'numeral' (because of finger-counting). 'Base' originally referred to a foundation or support; combined as 'digit-based', the meaning evolved into the modern sense 'founded on digits or numerical data'.