Orthorhombic is a term used in crystallography to describe a type of crystal system that has three unequal axes at right angles to each other. Some synonyms for this word include rectangular, oblong, square, cubic, and prism-like. The orthorhombic crystal system is characterized by minerals that exhibit strong cleavage in three directions at 90-degree angles. Other crystal systems include monoclinic, triclinic, tetragonal, and hexagonal. Orthorhombic crystals can often be found in minerals such as calcite, aragonite, and barite. Understanding crystal systems and their properties can be useful in identifying minerals and understanding their physical and chemical properties.