(Ra`di*at"i*form) 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) 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
(Ra"di*a*tive) a. Capable of radiating; acting by radiation. Tyndall.
(Ra"di*a`tor) 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) 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 &radic (originally the letter r, the initial of radix, root),
placed before any quantity, denoting that its root is to be extracted; thus, &radica, or &radic To indicate
any other than the square root, a corresponding figure is placed over the sign; thus, &cuberoot;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
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.