semi-solid

This term is primarily used in technical, scientific, and industrial contexts to describe materials that exhibit properties of both liquids and solids. It describes a state of matter where the substance is too firm to flow freely like a liquid but too soft to maintain a rigid shape like a solid. Common examples include gels, pastes, and certain types of ointments.

When used as a noun, the term refers to the substance itself. While it can be pluralized in a laboratory or industrial setting to describe different types of materials, it is frequently treated as a mass noun when referring to the general state of a specific substance.