That's because no one really defined what "equity" means in the first place. In absence of a clear definition, people just fill in whatever they want.
Just because you haven't bothered to look up what it means doesn't mean no one has defined it. This comment reminds me of the people who complain "the mainstream media isn't talking about XYZ" when they are, in fact, talking a lot about XYZ, but the complainant is only reading Facebook articles shared by their friends.
One might consider [this seminal paper](https://web.archive.org/web/20090612025522/http://bss.sfsu.e...) on the concept of social equity, and then google "equity" to see how institutions are using the term.
Most of them, you can see a connection between the ideas expressed in that paper and the definitions the modern institutions purport to believe in.
I also didn't bother to look up the meanings of equality, fairness or diversity. But those words are fairly straightforward and one learns them when one learns English.
"Equity" is one where the implied usage in corporate settings is pretty confusing given the standard meaning (see next para) of that word. So if my corporate bosses and HR are going to use that word, it is on them to educate and address the confusion of the audience.
Dictionary definitions of equity: "the quality of being fair and impartial", "the value of the shares issued by a company". Assuming it's the former, what does my HR even mean when they say we should be "fair and impartial"? On the one hand, that's a given, like saying "we should obey all the laws". On the other hand, if we are not being fair and impartial, then HR should lay out specific ways in which we are not and also the specific remedies.
It doesn’t make you like some sort of prodigal genius to cite some Marxist garbage and pretend like yeah if we only did it right this 270th time it’d be perfect. Like you think you can do it better than stalin, huh? And even if you could, what makes you think someone wouldn’t take you out.
You can never have equity because people will never work equal equally as hard. That is a fundamental fact of humanity.