Definition of knack. 1  1 : a special ready capacity that is hard to analyze or teach. 2  2a : a clever trick or stratagemb : a clever way of doing something. 3  3 archaic : an ingenious device; broadly : toy, knickknack.
Medical Definition of gingivoplasty. plural. gingivoplasties. : a surgical procedure that involves reshaping the gums for aesthetic or functional purposes.
Pterygium, also known as surfer's eye, most often refers to a benign growth of the conjunctiva. A pterygium commonly grows from the nasal side of the conjunctiva. It is usually present in the palpebral fissure. It is associated with and thought to be caused by ultraviolet-light exposure (e.g., sunlight), low humidity, and dust.