This expanded definition --- of the possibility of "frontrunning" when in possession of confidential information --- is the context of the Khan & Lu paper the paper coauthor cites below to justify his use of the term in this Ethereum paper, and, of course, does not really apply here.

It's of course worth mentioning that in the US, "insider trading" is itself defined largely in terms of fiduciary duty. There's nothing wrong with developing and exploiting proprietary sources of tradable information; in fact, as Matt Levine points out, that's kind of the point of a market (to aggregate information and discover prices). What's really problematic is when you're given access to private information in confidence and then use that information to trade against the owners of that information.

(I imagine this is not new to you; just for the thread).