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Webster 1913 Edition

Radical

Rad′i-cal

(răd′ĭ-kal)
,
Adj.
[F., fr. L.
radicalis
having roots, fr.
radix
,
-icis
, a root. See
Radix
.]
1.
Of or pertaining to the root; proceeding directly from the root.
2.
Hence: Of or pertaining to the root or origin; reaching to the center, to the foundation, to the ultimate sources, to the principles, or the like; original; fundamental; thorough-going; unsparing; extreme;
as,
radical
evils;
radical
reform; a
radical
party.
The most determined exertions of that authority, against them, only showed their
radical
independence.
Burke.
3.
(Bot.)
(a)
Belonging to, or proceeding from, the root of a plant;
as,
radical
tubers or hairs
.
(b)
Proceeding from a rootlike stem, or one which does not rise above the ground;
as, the
radical
leaves of the dandelion and the sidesaddle flower
.
4.
(Philol.)
Relating, or belonging, to the root, or ultimate source of derivation;
as, a
radical
verbal form
.
5.
(Math.)
Of or pertaining to a radix or root;
as, a
radical
quantity; a
radical
sign. See below.
Radical axis of two circles
.
(Geom.)
See under
Axis
.
–
Radical pitch
,
the pitch or tone with which the utterance of a syllable begins.
Rush.
–
Radical quantity
(Alg.)
,
a quantity to which the radical sign is prefixed; specifically, a quantity which is not a perfect power of the degree indicated by the radical sign; a surd.
–
Radical sign
(Math.)
,
the sign √ (originally the letter r, the initial of radix, root), placed before any quantity, denoting that its root is to be extracted; thus, √a, or √(a + b). To indicate any other than the square root, a corresponding figure is placed over the sign; thus, ∛a, indicates the third or cube root of a.
–
Radical stress
(Elocution)
,
force of utterance falling on the initial part of a syllable or sound.
–
Radical vessels
(Anat.)
,
minute vessels which originate in the substance of the tissues.
Syn. – Primitive; original; natural; underived; fundamental; entire.
–
Radical
,
Entire
. These words are frequently employed as interchangeable in describing some marked alteration in the condition of things. There is, however, an obvious difference between them. A radical cure, reform, etc., is one which goes to the root of the thing in question; and it is entire, in the sense that, by affecting the root, it affects in an appropriate degree the entire body nourished by the root; but it may not be entire in the sense of making a change complete in its nature, as well as in its extent. Hence, we speak of a radical change; a radical improvement; radical differences of opinion; while an entire change, an entire improvement, an entire difference of opinion, might indicate more than was actually intended. A certain change may be both radical and entire, in every sense.

Rad′i-cal

(răd′ĭ-kal)
,
Noun.
1.
(Philol.)
(a)
A primitive word; a radix, root, or simple, underived, uncompounded word; an etymon.
(b)
A primitive letter; a letter that belongs to the radix.
The words we at present make use of, and understand only by common agreement, assume a new air and life in the understanding, when you trace them to their
radicals
, where you find every word strongly stamped with nature; full of energy, meaning, character, painting, and poetry.
Cleland.
2.
(Politics)
One who advocates radical changes in government or social institutions, especially such changes as are intended to level class inequalities; – opposed to conservative.
In politics they [the Independents] were, to use the phrase of their own time, “Root-and-Branch men,” or, to use the kindred phrase of our own,
Radicals
.
Macaulay.
3.
(Chem.)
(a)
A characteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom.
As a general rule, the metallic atoms are basic
radicals
, while the nonmetallic atoms are acid
radicals
.
J. P. Cooke.
(b)
Specifically, a group of two or more atoms, not completely saturated, which are so linked that their union implies certain properties, and are conveniently regarded as playing the part of a single atom; a residue; – called also a
compound radical
. Cf.
Residue
.
4.
(Alg.)
A radical quantity. See under
Radical
,
Adj.
An indicated root of a perfect power of the degree indicated is not a
radical
but a rational quantity under a radical form.
Davies & Peck (Math. Dict.)
5.
(Anat.)
A radical vessel. See under
Radical
,
Adj.

Webster 1828 Edition

Radical

RAD'ICAL

,
Adj.
[L. radicalis, from radix, root. See Race and Ray.]
1.
Pertaining to the root or origin; original; fundamental; as a radical truth or error; a radical evil; a radical difference of opinions or systems.
2.
Implanted by nature; native; constitutional; as the radical moisture of a body.
3.
Primitive; original; underived; uncompounded; as a radical word.
4.
Serving to origination.
5.
In botany, proceeding immediately from the root; as a radical leaf or peduncle.

RAD'ICAL

, n.
1.
In philology, a primitive word; a radix, root, or simple underived uncompounded word.
2.
A primitive letter; a letter that belongs to the radix.
3.
in chimistry, an element, or a simple constituent part of a substance, which is incapable of decomposition.
That which constitutes the distinguishing part of an acid, by its union with oxygen.
Compound radical is the base of an acid composed of two or more substances. Thus a vegetable acid having a radical composed of hydrogen and carbon, is said to be an acid with a compound radical.
Radical quantities, in algebra, quantities whose roots may be accurately expressed in numbers. The term is sometimes extended to all quantities under the radical sign.

Definition 2024

radical

radical

English

Adjective

radical ‎(comparative more radical, superlative most radical)

  1. Favoring fundamental change, or change at the root cause of a matter.
    His beliefs are radical.
  2. (botany, not comparable) Pertaining to a root (of a plant).
  3. Pertaining to the basic or intrinsic nature of something.
    • Burke
      The most determined exertions of that authority, against them, only showed their radical independence.
  4. Thoroughgoing; far-reaching.
    • 2012 January 1, Donald Worster, “A Drier and Hotter Future”, in American Scientist, volume 100, number 1, page 70:
      Phoenix and Lubbock are both caught in severe drought, and it is going to get much worse. We may see many such [dust] storms in the decades ahead, along with species extinctions, radical disturbance of ecosystems, and intensified social conflict over land and water. Welcome to the Anthropocene, the epoch when humans have become a major geological and climatic force.
    The spread of the cancer required radical surgery, and the entire organ was removed.
  5. (linguistics, not comparable) Of or pertaining to the root of a word.
  6. (linguistics, not comparable, of a sound) Produced using the root of the tongue.
  7. (chemistry, not comparable) Involving free radicals.
  8. (mathematics) Relating to a radix or mathematical root.
    a radical quantity; a radical sign
  9. (slang, 1980s & 1990s) Excellent; awesome.
    That was a radical jump!

Derived terms

Related terms

Synonyms

  • (pertaining to the basic or intrinsic nature of something): fundamental
  • (linguistics, in reference to words): primitive

Antonyms

Coordinate terms

Translations

Noun

radical ‎(plural radicals)

  1. (historical: 19th-century Britain) A member of the most progressive wing of the Liberal Party; someone favouring social reform (but generally stopping short of socialism).
  2. (historical: early 20th-century France) A member of an influential, centrist political party favouring moderate social reform, a republican constitution, and secular politics.
  3. A person with radical opinions.
  4. (arithmetic) A root (of a number or quantity).
  5. (linguistics) In logographic writing systems as the Chinese writing system, the portion of a character (if any) that provides an indication of its meaning, as opposed to phonetic.
  6. (linguistics) In Semitic languages, any one of the set of consonants (typically three) that make up a root.
  7. (chemistry) A group of atoms, joined by covalent bonds, that take part in reactions as a single unit.
  8. (organic chemistry) A free radical.

Derived terms

Translations

Anagrams

Catalan

Adjective

radical m, f ‎(masculine and feminine plural radicals)

  1. radical

Noun

radical m, f ‎(plural radicals)

  1. radical

French

Pronunciation

Adjective

radical m ‎(feminine singular radicale, masculine plural radicaux, feminine plural radicales)

  1. radical

Galician

Noun

radical m ‎(plural radicais)

  1. radical (in various senses)

Portuguese

Noun

radical m (plural radicais)

  1. (linguistics) root (primary lexical unit of a word)

Synonyms

Noun

radical m f (plural radicais)

  1. radical (person holding unorthodox views)

Synonyms

Adjective

radical m, f ‎(plural radicais, comparable)

  1. radical (favouring fundamental change)
  2. drastic; extreme
  3. (Brazil, slang) excellent; awesome; thrilling
  4. (sports) extreme (dangerous)

Spanish

Adjective

radical m, f ‎(plural radicales)

  1. radical

Noun

radical m ‎(plural radicales)

  1. radical

Etymology

From French radical, from Late Latin radicalis ‎(“of or pertaining to the root, having roots, radical”), from Latin radix ‎(“root”); see radix.

Pronunciation

  • enPR: rădʹĭk-əl, IPA(key): /ˈɹædɪkəl/
  • Homophone: radicle

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