Radical

Radical may refer to:

Politics and ideology

Political radicalism
Radicalism (historical), the Radical Movement that began in late 18th century Britain and spread to continental Europe and Latin America in the 19th century
Radical Party (disambiguation), one of a number of political parties around the world
Radicals (UK), parliamentary progressives who were part of the nineteenth-century Liberal coalition
Radicalization

Radical chic, a term coined by Tom Wolfe to describe the pretentious adoption of radical causes by celebrities, socialites, and high society
Radical feminism, a current within feminism that focuses on patriarchy as a system of power
Radical Islam, or Islamic extremism
Radical veganism, a radical interpretation of veganism, usually combined with anarchism
Radical Reformation, an Anabaptist movement concurrent with the Protestant Reformation

Radical expression involving roots, also known as an Nth root
Radical symbol (√), used to indicate the square root and other roots
Radical of an algebraic group, a concept in algebraic group theory
Radical of an ideal, an important concept in abstract algebra
Radical of a ring, an ideal of "bad" elements of a ring
Radical of a module, a component in the theory of structure and classification
Jacobson radical, consisting of those elements in a ring R that annihilate all simple right R-modules
Nilradical of a ring, a nilpotent ideal which is as large as possible
Nilradical of a Lie algebra, a nilpotent ideal which is as large as possible
Radical of an integer, in number theory, the product of the primes which divide an integer
Left (or right) radical of a bilinear form, the subspace of all vectors left (or right) orthogonal to every vector
Radical of a Lie algebra, a concept in Lie theory

Radical (chemistry), an atom, molecule, or ion with unpaired valence electron(s), that is likely to take part in chemical reactions
Radical surgery, surgery carried out in which diseased tissue or lymph nodes are removed from a diseased organ

Radical verb (or 'radical-changing' verb), in inflected languages, a verb with strong inflection
Root (linguistics), also called a "radical", the form of a word after any prefixes and suffixes are removed
Radical (Chinese characters), part of a Chinese character under which it is indexed in a dictionary (also called bùshǒu 部首)
Radical, one of the three consonants in a Semitic root
Radical consonant, a consonant articulated with the root of the tongue

Radical Sportscars, an English sports car maker
Radical Entertainment, a defunct video game developer based in Vancouver, Canada
Free Radical Design, a video game developer based in Nottingham, England
Free Radical Centre, a centre for free radical chemistry and biotechnology that was established in 2005

Radical (film), an upcoming film
Radical Baroque, an architectural style characterized by the curvature of walls and intersection of oval spaces