(mathematics) The line containing the locus of points from which the segments respectively tangent to two given circles have equal length.

(chemistry) A positively charged radical ion.

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

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

(chemistry) A negatively charged radical ion.

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

(chemistry, physics) A molecule, ion or atom that has one or more unpaired electrons, and which is generally highly reactive (and therefore often occurs only as a transient species).

(geometry) A point at which the radical lines of three circles meet. / Pertaining to radical centrism.

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.