What does the word solid mean

Sol·id ˈsäləd / adjective 1. firm and stable in shape; not liquid or fluid."the stream was frozen solid" synonyms: hard, rock-hard, rigid, firm, solidified, set, frozen, concrete"the ice cream was solid" 2. not hollow or containing spaces or gaps."a sculpture made out of solid rock" noun1. a substance or object that is solid rather than liquid or fluid.

Solid is one of the states of matter. Its like you can't see through it or go through it, but you can see it. Like humans, we are solid.