@gamingonlinux simple:

A game made by one or multiple "independent developers" aka. neither access to resources nor funding by big publishers and/or developers.

Meaning <100 people (if we count in all bought-in assets and playtesters) may and usually <10 people (employed directly or indirectly) and a budget <€ 1M.

Anyhing above is #SmallStudio and not #IndieDev!