Hi,
I’m new to this forum and first of all I’d like to thank for its existence and support – I feel it really helps you to see your own experience in broader perspective.

I have doubts whether I should footnote something or not. The whole thing is kinda complicated, so thanks for reading all of it. I wrote a paper discussing concept A in the works of B and also the reception of this problem in other scholars’ papers. Let’s say that authors C&D, whose paper I comment on polemically in my text, used a definition of A from a source X. A is a term from another discipline and B employed it as a metaphor, X is basically a dictionary of terms of this other discipline, so it’s nothing sophisticated. I consulted the X and also other dictionaries, but the X definition suits my purpose best (as was in C&D’s case, probably). So I cite X in my paper and I include less then C&D did, but it’s the same passage. Should I somehow indicate in a footnote that the same citation was used by the authors whose text I discuss? I mean, I don’t want to make an impression that I’m feeding on their idea to use this definition, I’m pointing out what I see as their flaws and I’m not giving them credit for the idea of using this X source. I’d reference them if I hadn’t consulted the X myself, because then it would be secondary source citation, but this is not the case, because I consulted X and also other sources. What I’m worried about is that no one except me knows that I did, so it’s impossible to tell the difference between fair usage and secondary source plagiarism just from the text.

I may be overanalysing this but when it comes to research ethics I’m very concerned to do everything properly.
Thanks for any advice!