Discrimination is discrimination everywhere, as it applies to all activities where people make distinction and treat some things, people or activities differently.
But I'm arguing that when you hear "X is discrimination" then it's wrong to automatically imply that X is bad or X should be changed - there's just a narrow subset of discrimination that's immoral and should be avoided; and there's a narrow subset of discrimination that's illegal discrimination (there's some overlap between these two subsets but they are not exactly the same of course), but most discrimination - and certainly the default situation - is just reasonable human activity of us applying common sense and acting according to the specific situation instead of blindly acting the same no matter what like robots would, it's completely normal to adapt to the specific person and act differently to be most suitable with them, make adjustments and custom approaches for different individuals which definitely is discrimination but there's nothing a priori wrong with that. For example, custom pricing is one form of discrimination - offering a discount for students or senior peole is certainly discrimination, but we generally consider that it's entirely appropriate.
And in certain cases a lack of discrimination would be completely immoral - for example, the concept of "reasonable accomodations" is a requirement for discrimination; for example, a policy that forbids electronic devices in an exam does not discriminate in any way and applies equally to anyone (in colloquial language one might call it a "discriminatory policy" but that's wrong; perhaps I'm nitpicking on that but it a misuse of words to mean their exact opposite), but as it forbids hearing aids for people who need them, then that non-discrimination is bad; and also simply equally allowing all devices would be bad for other reasons, so ADA and equivalent laws require to discriminate and apply different rules to people with different abilities.
So if you see a practice that seems definitely bad and harmful, then "is it discrimination?" is the wrong question to ask, since it's very likely that it may be harmful but not discrimination, or it may be discrimination but nothing wrong with it; these aren't edge cases, the overlap is just partial. The proper question to ask is whether the criteria of the discrimination is fair (the up-thread issue of discriminating upon wealth certainly is debatable whether that should or should not be acceptable) and whether the results of that discrimination are appropriate.