Has “Founder” become a job title?

A ex-colleague working for a local startup mentioned to me that one of the three co-founders of the company had agreed to "step down" as a co-founder due to family commitments (not being able to put in the requisite hours). It made me wonder if I have missed a subtlety as to how the term is currently being used.

How would you define a "founder"? Is it literally, someone who was involved in founding a company or does it refer to a degree of commitment, risk, or other intangible asset.