The term "S-bend" refers to a curved or sinuous shaped piping structure typically found in plumbing or waste management systems. A few synonyms for S-bend include "U-bend", "trap", "curve", "loop", and "bend". The U-bend derives its name from the shape of the piping structure, which adheres to a consistent "U" shape. Similarly, "trap" and "loop" refer to the design of the bend, which traps water or waste material and prevents noxious gases from rising up into living spaces. On the other hand, "curve" and "bend" are more general terms which refer to any type of bending or curving of a pipe.