Digit
来自Big Physics
late Middle English: from Latin digitus ‘finger, toe’; digit (sense 1) arose from the practice of counting on the fingers.
wiktionary
From Middle English digit, from Latin digitus(“a fingerbreadth; a number”). Doublet of digitus.
etymonline
digit (n.)
late 14c., "numeral below 10," from Latin digitus "finger or toe" (also with secondary meanings relating to counting and numerals), considered to be related to dicere "to say, speak" (from PIE root *deik- "to show," also "pronounce solemnly"). The numerical sense is because numerals under 10 were counted on fingers. The "finger or toe" sense in English is attested from 1640s.
