concrete

(noun) a strong hard building material composed of sand and gravel and cement and water.

(verb) cover with cement. Example: "Concrete the walls."

(verb) form into a solid mass; coalesce.

(adj) capable of being perceived by the senses; not abstract or imaginary. Synonyms: concrete (vs. abstract). Example: "Concrete objects such as trees."

(adj) formed by the coalescence of particles.