'orthorhombic' originates from New Latin/scientific formation based on Greek, specifically from Greek 'orthos' and 'rhombos', where 'orthos' meant 'straight' or 'correct' and 'rhombos' meant 'a rhombus (diamond-shaped figure)'.

'orthorhombic' was formed in scientific/technical usage (via New Latin/Modern scientific coinage and Continental languages such as German 'orthorhombisch') to name a crystal system; it entered modern English as a technical adjective describing that system.

Initially formed to describe a shape related to a 'straight' rhombus or rhombic lattice element; over time it became the standard term for the specific crystal system characterized by three unequal, mutually perpendicular axes.