Crena is a term used in anatomy and dental sciences to refer to the small, shallow grooves or fissures on the surface of teeth or bones. Synonyms for crena include furrow, groove, slit, indentation, notch, incision, cut and channel. These terms can be used interchangeably to describe the small ridges and hollows found in various parts of the body. In dental science, crenas are commonly found between the cusps on the chewing surface of molars, and often require special attention during dental cleaning. Understanding the different terms that can be used to describe crenas is essential to effectively communicate about anatomical structures and medical conditions.