Etymology: Middle English solide, from Middle French, from Latin solidus; akin to Greek holos whole — more at safe
Date: 14th century
a. being without an internal cavity <a solid ball of rubber> b. (1) printed with minimum space between lines (2) joined without a hyphen <a solid compound> c. not interrupted by a break or opening <a solid wall> 2. having, involving, or dealing with three dimensions or with solids <a solid configuration> 3. a. of uniformly close and coherent texture ; not loose or spongy ; compact b. possessing or characterized by the properties of a solid ; neither gaseous nor liquid <solid waste> 4. of good substantial quality or kind <solid comfort>: as a. sound <solid reasons> b. made firmly and well <solid furniture> c. reliable <a solid performer> 5. a. having no break or interruption <waited three solid hours> b. unanimous <had the solid support of the party> c. intimately friendly or associated <solid with the boss> 6. a. prudent; also well established financially b. serious in purpose or character 7. of one substance or character: as a. entirely of one metal or containing the minimum of alloy necessary to impart hardness <solid gold> b. of a single color • solidly adverb • solidness noun II. noun Date: 15th century 1. a geometrical figure or element (as a cube or sphere) having three dimensions — see volume table 2. a. a substance that does not flow perceptibly under moderate stress, has a definite capacity for resisting forces (as compression or tension) which tend to deform it, and under ordinary conditions retains a definite size and shape b. the part of a solution or suspension that when freed from solvent or suspending medium has the qualities of a solid — usually used in plural <milk solids> 3. something that is solid: as a. a solid color b. a compound word whose members are joined together without a hyphen III. adverb Date: 1651 in a solid manner; also unanimously
New Collegiate Dictionary. 2001.