Basically, the process of making something wet requires a liquid (usually water) to actually stick to it, through intermolecular forces. That's slightly more narrow a requirement than the "needs to touch water" that's commonly thrown around. A lotus flower or water repellent jacket doesn't get wet, even if you spray water on it, the droplets don't actually stick to the surface.

Now, water molecules stick to each other as well, that's called surface tension. But wetness, at least in physics, is defined at an interface between two mediums, a liquid and a solid, or two liquids that don't mix