In chemistry:

• A radical (chemistry) is an atom, molecule, or ion, that is likely to take part in chemical reactions

In mathematics:

• Radical symbol (√), a symbol used to indicate the square root or nth root
• 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, in ring theory, a radical of a ring is an ideal of "bad" elements of the ring
• Radical of a module, in the theory of modules, the radical of a module is a component in the theory of structure and classification
• Jacobson radical, the Jacobson radical of a ring, R, consists of those elements in R that annihilate all simple right R-modules
• Nilradical of a ring, the nilradical of a commutative ring is a nilpotent ideal, which is as large as possible
• Nilradical of a Lie algebra, the nilradical of a Lie algebra is a nilpotent ideal, which is as large as possible
• Radical of an integer, in number theory, the radical of an integer is the product of the primes which divide that 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

In medicine:

• Radical surgery, surgery carried out in extreme circumstances and/or with extensive treatment

In linguistics:

• In an inflected language such as English or Spanish, the radical verbs (also called 'radical-changing') are exceptions to the standard patterns of word change (e.g., to be is in most Indo European languages).
• Root (linguistics), also called a "radical", the form of a word after any prefixes and suffixes are removed
• Radical (Chinese character), 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

In politics:

• 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 left, another term for the far left
• Radical right, another term for the far right
• Radical Republicans, a member of an influential group of American politicians during the Civil War reconstruction
• Radical Party, one of a number of political parties around the world
• Radicals (UK), parliamentary progressives who were part of the nineteenth-century Liberal coalition

In religion:

• Radical Reformation, an Anabaptist movement concurrent with the Protestant Reformation
• Radical: Taking Back Your Faith from the American Dream, 2010 Christian book

In culture:

• Radical feminism, a current within feminism that focuses on patriarchy as a system of power
• Radical veganism, a radical interpretation of veganism, usually combined with anarchism
• Radical chic, a term coined by Tom Wolfe to describe the pretentious adoption of radical causes by celebrities, socialites, and high society

In architecture:

• Radical Baroque, an architectural style characterized by the curvature of walls and intersection of oval spaces

In music:

• Radical (mixtape), a mixtape by the alternative hip hop collective OFWGKTA
• "Radicals" (song), a song by Tyler, The Creator from his album Goblin
• Free Radicals (band), a jazz-funk musical group from Houston, Texas
• New Radicals, an American pop rock band from the 1990s
• Radical (album), Smack's fourth studio album, released in 1988

Brands, titles and proper names:

• Radical Sportscars, an English sports car maker
• Free Radical Design, a video game developer based in Nottingham, England

Jill Sparrow - Non-fiction Work
... Radical Melbourne, published by Vulgar Press, written in collaboration with her brother Jeff Sparrow, presents a guide through the first hundred years of political radicalism in Melbourne, focusing ... It concentrates on identifying the physical traces of radical Melbourne, in the hope that geographical familiarity will provide a cultural and ... Radical Melbourne is a secret history of Melbourne, illustrated by rarely-seen images from the archives of the State Library of Victoria ...
... Radical mastectomy is a surgical procedure in which the breast, underlying chest muscle (including pectoralis major and pectoralis minor), and lymph nodes of the axilla are removed as a treatment for breast cancer. 90% of the women being treated for breast cancer in the US underwent the Halsted radical mastectomy ... to 1975, if a woman had a lump in her breast, and the lump proved to be malignant, a radical mastectomy was performed immediately, in the belief that it was necessary to prevent the further spread of the ...
... Radical perineal prostatectomy is a surgical procedure wherein the prostate gland is removed through an incision in the area between the anus and the scrotum (perineum) ... Radical perineal prostatectomy is less commonly used than another surgery such as the open radical retropubic prostatectomy or the robot assisted laparoscopic radical retropubic prostatectomy ... When the cancer is small and confined to the prostate, radical perineal prostatectomy achieves the same rate of cure as the retropubic approach but less blood is lost and recovery is faster ...
Ascorbic - Antioxidant Mechanism
... It can be oxidized by one electron to a radical state or doubly oxidized to the stable form called dehydroascorbic acid ... oxidants of the reactive oxygen species, such as the hydroxyl radical formed from hydrogen peroxide ... Such radicals are damaging to animals and plants at the molecular level due to their possible interaction with nucleic acids, proteins, and lipids ...

### Famous quotes containing the word radical:

What makes it so plausible to assume that hypocrisy is the vice of vices is that integrity can indeed exist under the cover of all other vices except this one. Only crime and the criminal, it is true, confront us with the perplexity of radical evil; but only the hypocrite is really rotten to the core.
Hannah Arendt (1906–1975)

The gift of loneliness is sometimes a radical vision of society or one’s people that has not previously been taken into account.
Alice Walker (b. 1944)

Every genuine boy is a rebel and an anarch. If he were allowed to develop according to his own instincts, his own inclinations, society would undergo such a radical transformation as to make the adult revolutionary cower and cringe.
Henry Miller (1891–1980)