Well, besides OSI's definition -- which I understand is being questioned in this comments section, so I suppose mentioning it is begging the question -- most of the bibliography and articles out there use "open source" in the sense I mentioned.
Microsoft was also aware of the accepted meaning, which is why they introduced their "Shared Source Initiative" back in the old days (note how deviously careful they were about the naming).
Honestly, this comment section is the first time I've heard about the OSI, I guess whenever I read articles that use "open source" I've assumed a definition that may not be technically correct. I would hazard a guess that my definition is probably more widely held but that could just be my personal bias.
But that's not actually the most commonly accepted definition of open source. It means something else, as widely understood by the software community.