Can region be defined outside of the theme's .info file? Basically I'm trying to reverse-engineer a theme that was developed by another guy. The problem is that I'm not yet quite firm on Drupal ground. 

So I'm looking onto a management page for blocks and see a specific region, which is not defined in theme's .info file...

Can regions be defined elsewhere? Or inherited from somewhere else (another theme maybe)?

UPDATE:
Since to inherit something this should be a sub-theme, which should be denoted by:  


  base theme = themeName


line in themeName.info file. But there is no such line in this theme... :( This undefined region should be coming from somewhere else...
Drupal 7 has 5 default regions: 


regions[sidebar_first] = Left sidebar
regions[sidebar_second] = Right
sidebar
regions[content] = Content
regions[header] = Header
regions[footer] = Footer
regions[highlighted] = Highlighted
regions[help] = Help


Regions aren't inherited by parent themes: https://drupal.org/node/225125. 

If I'm not mistaken you used to be able to define regions in theme_region(), but I believe that's no longer being used.