A monocline is a geological formation characterized by a fold in rock layers that dip in one direction while remaining relatively flat in the other. This term can be used synonymously with a variety of other geological terms, including a fault bend, an anticline, and a syncline. A fault bend is a type of fault where the associated rock layers display a curved or bent appearance due to the orientation of the fault. An anticline is a folding in which the rock layers are arched upward, while a syncline is a folding in which the rock layers are arched downward. All of these terms describe different types of rock formations with distinct geologic features.