compound radical

Radical Rad"i*cal (r[a^]d"[i^]*kal), n. 1. (Philol.) (a) A primitive word; a radix, root, or simple, underived, uncompounded word; an etymon. (b) A primitive letter; a letter that belongs to the radix. [1913 Webster]

The words we at present make use of, and understand only by common agreement, assume a new air and life in the understanding, when you trace them to their radicals, where you find every word strongly stamped with nature; full of energy, meaning, character, painting, and poetry. --Cleland. [1913 Webster]

2. (Politics) One who advocates radical changes in government or social institutions, especially such changes as are intended to level class inequalities; -- opposed to conservative. [1913 Webster]

In politics they [the Independents] were, to use the phrase of their own time, ``Root-and-Branch men,'' or, to use the kindred phrase of our own, Radicals. --Macaulay. [1913 Webster]

3. (Chem.) (a) A characteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom. [1913 Webster]

As a general rule, the metallic atoms are basic radicals, while the nonmetallic atoms are acid radicals. --J. P. Cooke. [1913 Webster] (b) Specifically, a group of two or more atoms, not completely saturated, which are so linked that their union implies certain properties, and are conveniently regarded as playing the part of a single atom; a residue; -- called also a {compound radical}. Cf. {Residue}. [1913 Webster]

4. (Alg.) A radical quantity. See under {Radical}, a. [1913 Webster]

An indicated root of a perfect power of the degree indicated is not a radical but a rational quantity under a radical form. --Davies & Peck (Math. Dict.) [1913 Webster]

5. (Anat.) A radical vessel. See under {Radical}, a. [1913 Webster]