From Online Dictionary of Crystallography
Revision as of 09:16, 11 December 2017 by BrianMcMahon (Tidied translations.)
Mériédrie (Fr). Meroedrie (Ge). Meriedria (It). 欠面像 (Ja). Meroedria (Sp).
The point group of a crystal is called merohedry if it is a subgroup of the point group of its lattice. It is a hemihedry (tetartohedry, ogdohedry) if it is a subgroup of index 2 (4, 8) of the point group of its lattice.