noun
: a crystal system characterized by three equal and interchangeable axes at equal angles to each other and usually classed as a division of the hexagonal system — compare tetragonal system
noun
: a crystal system characterized by three equal and interchangeable axes at equal angles to each other and usually classed as a division of the hexagonal system — compare tetragonal system
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012