Definition of Stenosis

Stenosis: A narrowing, as in:

• aortic stenosis (narrowing of the aortic valve of the heart),
• pulmonary stenosis (narrowing of the pulmonary valve of the heart),
• pyloric stenosis (narrowing of the outlet of the stomach), and
• spinal stenosis (narrowing of the vertebral canal).

From the Greek "stenos" meaning narrow.