what definition are you using, btwindie = small and independent
I think small team size is an important factor that changes the nature of game development and resulting games significantly. It's also the quantifiable factor that is behind the more nebulous terms like "indie spirit" or what have you. It's also less exclusive than "indie spirit"... because so what if they have a lot of money or want to, e.g., make a military shooter or something like that? They'll still do it much differently than a large company.
Basically, if you Google "indie games" you should get results that let you see how small, independent game studios make games, what kinds of games they can make, where they hang out, etc. Maybe you're working for a big company and thought about making your own games... well, boom, you can see what's possible and where to start learning.
Some people think "indie" is a stupid term, but in that context, at least, it's very useful. "Wow, a few people made that?
And their are entire communities based around making games this way? Alright, I'm inspired, let's do it."