Agreed. As with all rules there are always exceptions. I say this applies to concepts that are ubiquitous across unrelated codebases. id, repo, min, max, and enum are some that come to mind. Otherwise, all business domain terms should always be spelled out in full in the same way people refer to them in speech (ie, their ubiquitous language). So the only time acronyms are ok here is if that is how people talk about the particular term in every day speech (like "sku" instead of "stock keeping unit").