noun
uniaxial crystal
Technical term in crystallography and optics for a crystal with a single optic axis.
方解石は一軸性結晶の代表例である。
Calcite is a typical example of a uniaxial crystal.
二軸性結晶 has two optic axes, while 一軸性結晶 has only one.
Compound of 一軸 (one axis) + 性 (nature) + 結晶 (crystal).