Interface Translation: Separate Drupal interface strings from theme strings?
Looks like you are looking for contexts. In t documentation:


  Parameters
  
  
  $string: A string containing the English string to translate.
  $args: An associative array of replacements to make after translation. Based on the first character of the key, the value is escaped and/or themed. See format_string() for details.
  $options: An associative array of additional options, with the following elements:
  
  
  'langcode' (defaults to the current language): The language code to translate to a language other than what is used to display the page.
  'context' (defaults to the empty context): The context the source string belongs to.
  
  


You can have separate translations for separate contexts if you need.