To constrict is to become narrower at one place, or to make something narrower or more restrictive.(verb)
When your throat begins to close up because of an allergic reaction, this is an example of a time when your throat constricts.
See constrict in Webster's New World College Dictionary
Origin: < L constrictus, pp. of constringere: see constrain
See constrict in American Heritage Dictionary 4
verb con·strict·ed, con·strict·ing, con·stricts verb, transitive
Origin: Latin cōnstringere, cōnstrict-, to compress; see constrain.
Learn more about constrict