rad·i·cal /ˈrædɪkəl/ 形容詞
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,
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.
Usage: -- 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.
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, a.
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, a.
adj 1: (used of opinions and actions) far beyond the norm;
"extremist political views"; "radical opinions on
education"; "an ultra conservative" [syn: extremist,
2: markedly new or introducing radical change; "a revolutionary
discovery"; "radical political views" [syn: revolutionary]
3: arising from or going to the root; "a radical flaw in the
4: of or relating to or constituting a linguistic root; "a
radical verb form"
5: especially of leaves; located at the base of a plant or
stem; especially arising directly from the root or
rootstock or a root-like stem; "basal placentation";
"radical leaves" [syn: basal] [ant: cauline]
n 1: (chemistry) two or more atoms bound together as a single
unit and forming part of a molecule [syn: group, chemical
2: an atom or group of atoms with at least one unpaired
electron; in the body it is usually an oxygen molecule
than has lost an electron and will stabilize itself by
stealing an electron from a nearby molecule; "in the body
free radicals are high-energy particles that ricochet
wildly and damage cells" [syn: free radical]
3: a person who has radical ideas or opinions
4: a character conveying the lexical meaning of a logogram
5: a sign placed in front of an expression to denote that a
root is to be extracted [syn: radical sign]
6: (linguistics) the form of a word after all affixes are
removed; "thematic vowels are part of the stem" [syn: root,
root word, base, stem, theme]