› any one of the ten written numbers 0 to 9: Your password should contain a mixture of letters and digits. a four-digit/10-digit, etc. number
single/double/triple, etc. digit › used to say whether a number is between 1 and 9, between 10 and 99, between 101 and 999, etc.: He forecast that double-digit inflation would return. single-digit, etc. losses/gainsin single/double, etc. digits His popularity has fallen so far, his poll ratings are now in single digits. → Compare figure noun