I think you're thinking of the wrong definition for "meaning." OP is talking about what code in a language means, i.e. when I see the code say `1 + 2` does that

I think you're thinking of the wrong definition for "meaning." OP is talking about what code in a language means, i.e. when I see the code say `1 + 2` does that mean that the numbers signed or unsigned? Are they arbitrary precision or a certain size? What errors can result from the addition? Etc. It's essentially saying that you can look at a piece of code and formally define what it means to the computer