radical meaning and definition

RADICAL noun

Definition of radical (noun)

1. (chemistry) two or more atoms bound together as a single unit and forming part of a molecule
   • synonyms: chemical group, group
2. 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"
   • synonyms: free radical
3. a person who has radical ideas or opinions
4. (mathematics) a quantity expressed as the root of another quantity
5. a character conveying the lexical meaning of a logogram
6. (linguistics) the form of a word after all affixes are removed
   • "thematic vowels are part of the stem"
   • synonyms: base, root, root word, stem, theme

RADICAL adjective

Definition of radical (adjective)

1. (used of opinions and actions) far beyond the norm
   • "extremist political views"; "radical opinions on education"; "an ultra conservative"
   • synonyms: extremist, ultra
2. markedly new or introducing radical change
   • "a revolutionary discovery"; "radical political views"
   • synonyms: revolutionary
3. arising from or going to the root or source
   • "a radical flaw in the plan"
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"
   • synonyms: basal
   • antonym: cauline