(chemistry) The simplest member of a class of compounds, from which the others are formally obtained by substituting radicals for hydrogen atoms.

(chemistry) a substance consisting of molecules of one element or compound contained within the cage-like structure of another

(organic chemistry) Any compound containing carbon atoms covalently bound to other atoms.

(chemistry) any compound which contains more than eight formally assignable electrons in a valence shell directly associated with the central atom in direct bonding with a number of ligands

(inorganic chemistry) Any compound not containing carbon atoms. / (inorganic chemistry) Any compound containing carbon atoms ionically bound to other atoms.

(chemistry) a crystalline solid consisting of a host lattice containing voids into which guest atoms or molecules are inserted

(inorganic chemistry) any solid material, composed of two or more metal atoms in a definite proportion, that has a definite structure which differs from those of its constituent metals

(chemistry) Any compound containing atoms of three different elements

(chemistry) Any substance formed by the union of two or more chemical elements in a fixed ratio, the union being a chemical bond. / (informal, proscribed) Any single substance, either compound or element

(grammar) A compound word with spaces in it, for example, high school, school bus, or science fiction.