The term "open source" had no significant use to refer to software before the Open Source Initiative started promoting it. Previously, it was only intelligence industry jargon, meaning "publicly available information", which includes software that fails your "can read the source code" test. "Source" was used in the journalistic sense, not as in "source code". The correct term for software that passes your test but does not meet the Open Source Definition is "source available".
The OSI made a huge mistake in choosing to use an non-trademarkable borrowed term as their own trade industry term. The original (and quite long standing) use to refer to publicly available texts is still widely used, and English isn't a prescriptive language outside of legal frameworks like trademark. This is why you really should pick a trademarkable name when you try to define trade marks.
open source means the source code is openly available. That is it. Phrases that have intuitive meaning need to stop being co-opted.
If that meaning is "intuitive", why was it not used before the Open Source Initiative introduced their definition? The competing uses are the ones co-opting an existing phrase.
It’s perfectly intuitive to anyone with a brain. Never heard of OSI but they seem just about as pedantic, neurotic, and annoying with language as FSF.
Open source = I can view the source code. That’s what it means, that what it has always meant, and that what it will always mean. Simple as.