Ra"di*ate*ly (-t*l), adv. In a radiate manner; with radiation or
divergence from a center.
Ra"di*ate-veined` (-vnd`), a. (Bot.) Having the principal veins
radiating, or diverging, from the apex of the petiole; -- said of such
leaves as those of the grapevine, most maples, and the castor-oil
plant.
Ra`di*at"i*form (-t"*fôrm), a. (Bot.) Having the marginal florets
enlarged and radiating but not ligulate, as in the capitula or heads of
the cornflower. Gray.
Ra`di*a"tion (-"shn), n. [L. radiatio: cf. F. radiation.] 1. The act of
radiating, or the state of being radiated; emission and diffusion of
rays of light; beamy brightness.
2. The shooting forth of anything from a point or surface, like the
diverging rays of light; as, the radiation of heat.
Ra"di*a*tive (r"d**tv), a. Capable of radiating; acting by radiation.
Tyndall.
Ra"di*a`tor (-`tr), n. That which radiates or emits rays, whether of
light or heat; especially, that part of a heating apparatus from which
the heat is radiated or diffused; as, a steam radiator.
Rad"i*cal (rd"*kal), a. [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 (rd"*kal), n. 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.