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.
If you have always believed that everyone should play by the same rules and be judged by the same standards, that would have gotten you labeled a radical 60 years ago, a liberal 30 years ago and a racist today. Thomas Sowell
In the Muslim world, I had seen that men with white complexions were more genuinely brotherly than anyone else had ever been. That... was the start of a radical alteration in my whole outlook about 'white men.' Malcolm X