(chemistry) Any radical that also carries an electric charge; typically, the charge and unpaired electron are associated with the same atom.

(chemistry) A negatively charged radical ion.

(chemistry) A positively charged radical ion.

(chemistry) The uncharged radical H₂N^. formally derived from ammonia by removing a hydrogen atom; and any of its derivatives R₂N^.

(chemistry) The uncharged form of an aminoxide derived from hydroxylamines by removal of a proton; their structure is best represented as R₂NO^. <=> R₂N^(.+)-O⁻.

(mathematics) The plane containing the circle formed by the intersection of two spheres (or whose points have equal power with respect to two non-intersecting spheres)

plural of radical line

plural of radical axis

plural of radical ion

Any of a set of 214 radicals (the portion of a Chinese character that provides an indication of its meaning) introduced in the Zihui and named after the more popular Kangxi Dictionary. This set of radicals has become the standard for sorting and ordering Chinese characters.