My characterization would be that there's a spectrum here:

• 100% yes code: compilers, IDEs, scripting environments, databases, you wanna get something done, you are going to be specifying it in something that at the very least looks like traditional source code.
• Completely on the other side of the spectrum, traditional consumer-oriented software: word processor, web browser, accounting/bookkeeping (not spreadsheets though, we'll get to those), photo/video/audio editor, maps, music player, etc.

That first side of the spectrum is pretty easy to pin down. It has little to no metaphor or abstraction, and the pointy tip of this side is no metaphor at all, just writing machine code and piping it directly into the CPU. A higher level language will let you gloss over some details like registers, memory management, multithreading, maybe pretend you're manipulating little objects or mathematical functions instead of bits on a wire, but overall you are directing the computer to do computer things using computer language, and forced to think like a computer and learn what computers can and cannot do. This is, of course, the most powerful way to use a computer but is also completely inaccessible to almost everybody.

The second, I'd link together as all being software with a metaphor that is not particularly related to computing itself, but to something more real world. People edited music by physically splicing tapes together, an audio editor does an idealized version of that. Typewriters existed, and a word processor basically simulates that experience. Winamp wasn't much more than a boom box and a sleeve of CDs. There is usually a deliberate physicality and real-world grounding to the user's mental model of the software, even if it is doing things that would be impossible if the metaphor were literal. You don't need to use code, but you also don't get anything code-like out of it.

No-code is in between. It's intended for a similar audience as the latter category, who want a clear, easy-to-understand mental model that doesn't require a computer science degree, but it tries to enable that audience to perform code-like tasks. Spreadsheets are the original example of this; although they originate as a metaphor for paper balance sheets, the functions available in formulas fundamentally alter the metaphor to basically "imagine if you had a sheet of paper that could do literal magic" and at that point you're basically just describing a computer with a screen. Everything in a spreadsheet is very tactile, it's easy to see where your data is, but when you need to, you can dip into a light programming environment that regular people can still make work. In general, this is the differentiator for "no code" apps: enabling non-coders to dip their toes into modifying program behavior, scripting tasks, and building software. They're limited to what the tool provides, but the tool is trying to give them the power that actual coding would provide.

I'd never thought of WordPress as low-code, but I think that fits. Websites go beyond paper or magazines, and WordPress allows people to do things that would otherwise require code and databases and web servers and so on.