The term 'tightly compressed' can be summarized as 'DENSE'. DENSE is an adjective that describes something that is closely packed together, with little or no space between the parts. It is often used to describe materials such as liquids, gases, and solids. For example, a DENSE liquid would have a high concentration of particles, while a less DENSE liquid would have fewer particles. Similarly, a DENSE gas would have more molecules in a given volume than a less DENSE gas. In the context of solids, density is a measure of how much mass is contained in a given volume. A tightly compressed solid would have a higher density than a less compressed solid.