A root (of a number or quantity). • In logographic writing systems such as the Chinese writing system, the portion of a character used to index it. Often, but not always, this is also the portion indicating meaning; compare the following sense. • In logographic writing systems such as the Chinese writing system, the portion of a character (if any) that provides an indication of its meaning, as opposed to being wholly phonetic. • Any component of a logographic character, whether used for indexing or not, whether semantic or not. • In Celtic languages, the basic, underlying form of an initial consonant which can be further mutated under the Celtic initial consonant mutations. • In Semitic languages, any one of the set of consonants (typically three) that make up a root. • A group of atoms, joined by covalent bonds, that take part in reactions as a single unit. • A free radical. • Given an ideal I in a commutative ring R, another ideal, denoted Rad(I) or √, such that an element x ∈ R is in Rad(I) if, for some positive integer n, xⁿ ∈ I; equivalently, the intersection of all prime ideals containing I. • Given a ring R, an ideal containing elements of R that share a property considered, in some sense, "not good". • The intersection of maximal submodules of a given module. • The product of the distinct prime factors of a given positive integer. • A member of the most progressive wing of the Liberal Party; someone favouring social reform (but generally stopping short of socialism). • A member of an influential, centrist political party favouring moderate social reform, a republican constitution, and secular politics. • A person with radical opinions.