Use this domain for words related to numbers. Every language has a word for 'one', and a word for 'two'. These two numbers often have special words. So we have included a separate domain for 'one' and 'two'. In addition the numbers form a series (one, two, three...). Most languages have more than one series of numbers (first, second, third...). So we have also included a domain for each series of numbers that most languages have. Your language may have other series of numbers. Put them in the domain 'Number series'.