Stricture
An abnormal narrowing of a body passage, especially a tube or a canal.
The stricture may be due, for example, to scar tissue or to a tumor.
Stricture refers to both the process of narrowing and the narrowed part itself.
A stricture is also anything that closely restrains or limits.
Shakespeare used 'stricture' in the sense of strictness, as in 'A man of stricture and firm abstinence.'