- (a.) Of or pertaining to a radix or root; as, a radical quantity; a radical sign. See below.
- (a.) Of or pertaining to the root; proceeding directly from the root.
- (n.) A characteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom.
- (n.) A primitive letter; a letter that belongs to the radix.
- (a.) A radical vessel. See under Radical, a.
- (a.) 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.
- (n.) 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.
- (n.) A primitive word; a radix, root or simple, underived, uncompounded word; an etymon.
- (a.) 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.
- (n.) A radical quantity. See under Radical, a.
- (a.) Relating or belonging, to the root or ultimate source of derivation; as, a radical verbal form.
- (a.) Belonging to or proceeding from, the root of a plant; as, radical tubers or hairs.
- (n.) One who advocates radical changes in government or social institutions, especially such changes as are intended to level class inequalities; -- opposed to conservative.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). radical. Retrieved September 20, 2026, from http://smartdefine.org/radical/definitions/2052281 |
| Chicago | Webster's. 2011. "radical" http://smartdefine.org/radical/definitions/2052281 (accessed September 20, 2026). |
| Harvard | Webster's 2011, radical, Smart Define, viewed 20 September, 2026, <http://smartdefine.org/radical/definitions/2052281>. |
| MLA | Webster's. "radical" 27 May 2011. Web. 20 September 2026. <http://smartdefine.org/radical/definitions/2052281> |