Definition: The term "squamoepithelial" is a medical term that refers to the lining of the urinary bladder. It is composed primarily of squamous epithelium, which is an epithelial cell layer with cells with a rough surface and a flattened shape. These cells line the walls of the bladder and help to protect it from damage or infection. The squamoepithelial lining also plays a role in regulating the amount of urine that passes through the bladder during urination.