32.9 Some Add itional Terminology in Crystal lography 1. Single crystal ver sus polycrystal 1. For single crystals there is only one type of structure with same orientation Single crystals is characterized by anisotropy ov Wl same structure but different orientations. These smal Polycrystal consists of a lot of grain, small single crystals, single crystals are called grains. The boundaries between them are called grain boundaries§2.9 Some Additional Terminology in Crystallography ◆ Ⅰ. Single crystal versus polycrystal 1. For single crystals there is only one type of structure with same orientation. Single crystals is characterized by anisotropy. 2. Polycrystal consists of a lot of grain, small single crystals, with same structure but different orientations. These small single crystals are called grains. The boundaries between them are called grain boundaries