gen. A cleft or opening made by cutting or separation of parts; a rent, a fissure. Also figurative.

The action of cutting into something; esp. into some part of the body in surgery.

The action, or an act, of cutting or dividing. Now rare except with reference to surgery or anatomical operations.

= incision, n.

Surgery. Originally: †incision into an abscess, tumour, etc. (obsolete). In later use: opening of the capsule of the lens in order to treat a…

Surgery. A very small incision through which an endoscope or other instrument is passed in a minimally invasive procedure. See also compounds 2.