nonrestrictive clause: a subordinate clause that does not limit or restrict the meaning of the noun phrase it modifies
subordinate clause: a clause in a complex sentence that cannot stand alone as a complete sentence and that functions within the sentence as a noun or adjective or adverb
corpuscular radiation: a stream of atomic or subatomic particles that may be charged positively (e.g. alpha particles) or negatively (e.g. beta particles) or not at all (e.g. neutrons)