I think of meaning as the noun for which understand is the verb. You can know a fact, like the sky is blue, but what does it mean to say you understand the sky being blue? That you know why it happens? That's just more facts!

The sky is blue because of Rayleigh scattering, which is a special case of the Lorenz-Mie solution, which is itself a special case of Maxwell's equations for ideal spheres, which are themselves the special case of applying the Euler-Lagrange equation to the quantum electrodynamics Lagrangian. Which is, of course, just a gauge theory based on the phase invariance of the Dirac electron field. So that clears that up I think.

Even if you know what all that means, has your understanding increased? My argument would be no, unless it makes the sky being blue more meaningful to you.

An alternate explanation would be to imagine the sky as a lake, light as waves on the surface, and air molecules as little rubber duckies floating on top. When the duckies get hit by waves, they bob up and down, making more waves. Waves that move up and down faster make the duckies bob up and down faster, which also makes them bob up and down harder, so they make bigger waves in response. In other words, the sky is blue because blue light has a higher frequency and that gets the duckies all excited.

This explanation is more meaningful to me because it connects with intuitions I have about water and lakes and duckies, and helps me understand at a practical level. But it might also be meaningful to say something about gauge theory. After all, there is something profoundly fascinating about the idea that the answer to "why is the sky blue?" could start with "well, you know there's no way to tell which direction a circle is facing?" There is always some path, however twisty, from banal daily observations to the fundamental laws of the universe.

So I would argue that facts cannot be meaningful on their own. Even if tomorrow we found the grand universal codex containing every fact that ever was, we would still have a lot of work to do in understanding it: finding connections, correlations, and patterns; creating structure, rules, and theories; crafting interpretations, predictions, and stories. The data wouldn't satisfy us until we had found a way to break it down and digest it into meaning.

But it's not complete just to say meaning is the noun for which understand is the verb; there must be some equal and opposite verb. To understand meaning is to internalise it: to take it from the world and put it into your mind. What is it called when you externalise it, taking something from your mind and putting it out into the world?

That's creativity: the act of making meaning for others to understand.