An engine component, comprising: a body; and a plurality of cooling holes (220, 400) formed in the body, at least one of the cooling holes (220, 400) having an upstream end with a first diameter (d), and a downstream end having a cross-sectional shape with a leading edge and a trailing edge, wherein the leading edge includes - a first convex portion, - a first concave portion, and - a second convex portion, the first convex portion transitioning into the first concave portion, and the first concave portion transitioning into the second convex portion, wherein - the first convex portion is formed with a first construction circle having a second diameter approximately equal to the first diameter (d), - the first concave portion is formed with a third construction circle having a fourth diameter approximately equal to about 1.0 to about 1.2 times the first diameter (d), and - the second convex portion is formed with a second construction circle having a third diameter approximately equal to the first diameter (d), characterized in that the trailing edge includes - a second concave portion, - a third convex portion, and - a third concave portion, the second convex portion transitioning into the second concave portion, the second concave portion transitioning into the third convex portion, the third convex portion transitioning into the third concave portion, and the third concave portion transitioning back into the first convex portion. a body; and a plurality of cooling holes (220, 400) formed in the body, at least one of the cooling holes (220, 400) having an upstream end with a first diameter (d), and a downstream end having a cross-sectional shape with a leading edge and a trailing edge, wherein the leading edge includes - a first convex portion, - a first concave portion, and - a second convex portion, - a first convex portion, - a first concave portion, and - a second convex portion, the first convex portion transitioning into the first concave portion, and the first concave portion transitioning into the second convex portion, wherein - the first convex portion is formed with a first construction circle having a second diameter approximately equal to the first diameter (d), - the first concave portion is formed with a third construction circle having a fourth diameter approximately equal to about 1.0 to about 1.2 times the first diameter (d), and - the second convex portion is formed with a second construction circle having a third diameter approximately equal to the first diameter (d), - the first convex portion is formed with a first construction circle having a second diameter approximately equal to the first diameter (d), - the first concave portion is formed with a third construction circle having a fourth diameter approximately equal to about 1.0 to about 1.2 times the first diameter (d), and - the second convex portion is formed with a second construction circle having a third diameter approximately equal to the first diameter (d), characterized in that the trailing edge includes - a second concave portion, - a third convex portion, and - a third concave portion, - a second concave portion, - a third convex portion, and - a third concave portion, the second convex portion transitioning into the second concave portion, the second concave portion transitioning into the third convex portion, the third convex portion transitioning into the third concave portion, and the third concave portion transitioning back into the first convex portion.