Radical , from Late Latin radicalis "of roots" and from Latin radix "root", may refer to:
in science and mathematics
A radical (chemistry) is an atom , molecule , or ion which is likely to take part in chemical reactions .
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 branch of mathematics, 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 which 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 , a concept in number theory
Symmetric bilinear form , a concept in linear algebra
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 politics
Extremism , political standpoints that are perceived as revolutionary or extreme
in culture
in architecture
brands, titles and proper names
Radical Sportscars , an English sports car maker
Radical Entertainment , a video game developer based in Vancouver , Canada
Free Radical Design , a video game developer based in Nottingham , England
Free Radicals (band) , a jazz-funk musical group from Houston , Texas
Free Radical Centre , a centre for free radical chemistry and biotechnology that was established in 2005
Radical (Smack album) , Smack 's fourth studio album, released in 1988