lip
n.— «The area where the infield grass meets the dirt cutout has become what is better known in baseball parlance as a “lip.” And that lip is not small. Old timers used to call the feature a “suture,” recalling the ugly, bumpy scars made by back-in-the-day knee and elbow surgeries.» —“Sundberg infield a concern” by Tom Loewy Register-Mail (Galesburg, Illinois) May 21, 2004. (source: Double-Tongued Dictionary)