The reason nobody can define CRT is because it's not a definable thing. Like, try to define "deconstruction" or "cultural materialism" or "poststructuralism" or "new historicism" or "new criticism." They are disciplinary-specific heuristics for theorizing texts, literary and historical. They are not designed for teaching elementary school children history or high school kids structural racism. They are ways of understanding the world, which are more or less in vogue based on who is cool and who is smart and who is getting published.
The reason terms like "systemic racism" (though Stokely Carmichael talked about institutional racism in the 60s) and white privilege and all the other terms exist, those that seem so commonplace now but were nowhere to be found in regular discourse a decade ago, is because a set of scholars have been thinking and writing about race and society for decades.
All the sudden it has become cool to talk about and a bunch of white scholars have made headlines for writing about stuff black scholars have been saying for literally thirty years. It all coalesced under the vague CRT. While I'm surprised to hear that phdeac doesn't touch it in sociology of race classes, it is absolutely commonplace in literature fields. But (obviously) it is nothing like the way the media now describes it.
If you want a real answer about CRT, catamount, read abstracts or reviews of Sara Ahmed, Cord Whitaker, Henry Lewis Gates, Bell Hooks.
And if you're genuinely interested in an "academic" definition, read this from the ever-reliable Purdue OWL, which got me through my undergraduate citations:
https://owl.purdue.edu/owl/subject_...chools_of_criticism/critical_race_theory.html