Radical

Of or pertaining to the root; proceeding directly from the root.

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.

Belonging to, or proceeding from, the root of a plant; as, radical tubers or hairs.

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.

Relating, or belonging, to the root, or ultimate source of derivation; as, a radical verbal form.

Of or pertaining to a radix or root; as, a radical quantity; a radical sign. See below.

A primitive word; a radix, root, or simple, underived, uncompounded word; an etymon.

A primitive letter; a letter that belongs to the radix.

One who advocates radical changes in government or social institutions, especially such changes as are intended to level class inequalities; -- opposed to conservative.

A characteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom.

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.

A radical quantity. See under Radical, a.

A radical vessel. See under Radical, a.

(mathematics) a quantity expressed as the root of another quantity

(chemistry) two or more atoms bound together as a single unit and forming part of a molecule

an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule that 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"

(linguistics) the form of a word after all affixes are removed; "thematic vowels are part of the stem"

a character conveying the lexical meaning of a logogram

(used of opinions and actions) far beyond the norm; "extremist political views"; "radical opinions on education"; "an ultra conservative"