[rad-i-kuh l] /ˈræd ɪ kəl/
of or going to the root or origin; fundamental:
a radical difference.
thoroughgoing or extreme, especially as regards change from accepted or traditional forms:
a radical change in the policy of a company.
favoring drastic political, economic, or social reforms:
radical ideas; radical and anarchistic ideologues.
forming a basis or foundation.
existing inherently in a thing or person:
radical defects of character.
Grammar. of or relating to a root.
Botany. of or arising from the root or the base of the stem.
a person who holds or follows strong convictions or extreme principles; extremist.
a person who advocates fundamental political, economic, and social reforms by direct and often uncompromising methods.
Grammar. 1 (def 12).
(in Chinese writing) one of 214 ideographic elements used in combination with phonetics to form thousands of different characters.
of, relating to, or characteristic of the basic or inherent constitution of a person or thing; fundamental: a radical fault
concerned with or tending to concentrate on fundamental aspects of a matter; searching or thoroughgoing: radical thought, a radical re-examination
favouring or tending to produce extreme or fundamental changes in political, economic, or social conditions, institutions, habits of mind, etc: a radical party
(med) (of treatment) aimed at removing the source of a disease: radical surgery
(slang, mainly US) very good; excellent
of, relating to, or arising from the root or the base of the stem of a plant: radical leaves
(maths) of, relating to, or containing roots of numbers or quantities
(linguistics) of or relating to the root of a word
a person who favours extreme or fundamental change in existing institutions or in political, social, or economic conditions
(maths) a root of a number or quantity, such as ³√5, √x
(chem) Also radicle
(linguistics) another word for root1 (sense 9)
(in logographic writing systems such as that used for Chinese) a part of a character conveying lexical meaning
late 14c., in a medieval philosophical sense, from Late Latin radicalis “of or having roots,” from Latin radix (genitive radicis) “root” (see radish). Meaning “going to the origin, essential” is from 1650s. Radical sign in mathematics is from 1680s.
Political sense of “reformist” (via notion of “change from the roots”) is first recorded 1802 (n.), 1817 (adj.), of the extreme section of the British Liberal party (radical reform had been a current phrase since 1786); meaning “unconventional” is from 1921. U.S. youth slang use is from 1983, from 1970s surfer slang meaning “at the limits of control.” Radical chic is attested from 1970; popularized, if not coined, by Tom Wolfe. Radical empiricism coined 1897 by William James (see empiricism).
1630s, “root part of a word, from radical (adj.) Political sense from 1802; chemical sense from 1816.
radical rad·i·cal (rād’ĭ-kəl)
In politics, someone who demands substantial or extreme changes in the existing system.
In chemistry, an atom or group of atoms that has at least one electron free to participate in forming a chemical bond.
Note: In general, radicals are associated with chemical reactions that proceed rapidly.
noun, Geometry. 1. the line such that tangents drawn from any point of the line to two given circles are equal in length. noun 1. a line from any point of which tangents to two given circles are of equal length. It is the line joining the points of intersection of two circles
noun 1. the patronage of extremists or left-wing radicals by rich or famous people, as through invitations to social functions or public expressions of support. noun the adoption of radical views, dress, or lifestyle by members of the upper class; association of the upper class with radicals
noun 1. (in the philosophy of William James) the doctrine that the only proper subject matter of philosophy is that which can be defined in terms of experience, and that relations are a part of experience. 2. (def 3b).
noun, Mathematics. 1. an expression in which radical signs appear.