Horseshoe kidney, also known as ren arcuatus, is a congenital renal abnormality where the two kidneys fuse together at the lower end to form a U-shape. This condition affects about 1 in 500 individuals and is more common in males. Rather than using the term horseshoe kidney, medical professionals may use synonyms such as "renal fusion anomaly", "unilateral renal fusion", or "renal isthmus anomaly". Additionally, the term "suprarenal fusion" may be used to refer to the fusion of the adrenal gland with the horseshoe kidney. While the term horseshoe kidney is commonly used, it is important to recognize the various synonyms and alternative names within the medical field.