Multiple translations for one string in the same language

Hi, I need help translating one original string into different translations in the same language (on the same page). So one word in English would mean different words in German. How is that possible?

I usually create translatable string with the standard wordpress function(s)

__('string', 'domain')

_e('string', 'domain')

But when editing the .po file there is only one instance of that string (which is in most cases what you would want). Any idea?