Whale tail is a phrase describing the waistband of a thong or g-string when visible above the waistline of low-rise pants, shorts, or a skirt creating a shape resembling a whale's tail. The appearance of a whale tail is not always intentional
the distal birfucation, which is also known as the moustache, pitch fork, or whale's tail, in the left anterior descending coronary artery. , Eric J. Topol. Edition 4, illustrated. Elsevier Health Sciences, 2003. ISBN 0721694497.