Translation:Zero, one, two, three, four, five, six, seven, eight and nine are the ten digits.
One of the many meanings of the English word cipher (or cypher) is any of the Arabic numerals of zero through nine. Since the Esperanto word of cifero would be a direct cognate of the English word cipher, then the English word cipher might be considered a correct English translation of the Esperanto word cifero. Admittedly, the English word cipher has too many other meanings to be as precise as the simple English word of digit (though the English word digit also has other meanings and extensions beyond the individual Arabic numerals of zero through nine). For example, the English word cipher can also mean 'a code,' or 'a coded message.' The separate Esperanto word ĉifro stands for that other meaning of "code." So, a simple translation of the English word cipher for the Esperanto word cifero, when referring to the Arabic numerals of zero through nine, might be considered too ambiguous. Nonetheless, I wonder if the English word cipher would actually be an incorrect translation of the Esperanto word cifero when referring to the Arabic numerals of zero through nine. I'm perfectly happy to use the English word digit as a translation of the Esperanto word cifero, but I would also like to know whether the English word cipher is always an incorrect translation of the Esperanto word cifero.
Well, the original word is Arabic, صِفْر (sifr), meaning zero, empty. The Arabic word has been borrowed to Indo-European languages, like chiffre in French. As often happens with loan words the meaning changes. See https://en.wiktionary.org/wiki/cipher.
As a remark, Esperanto is clearly an Indo-European language, but not all European languages (= language originally spoken in Europe) are Indo-European ones. See https://en.wikipedia.org/wiki/Proto-Indo-European_language and for instance https://en.wikipedia.org/wiki/Uralic_languages.
Nope, because the word "digits" generally refers to single-character numbers. Well, that's a little bit of an over-simplification, but it gets the point across. 10 is made up of two digits, essentially two numeric characters: 1 and 0.
The numbers you are describing would be the first ten whole numbers, as zero is definitely not a whole number. But it is an integer... I forgot how confusing number sets are!