A graphite material with coherent crystallographic domains of limited size regardless of the perfection
and preferred orientation (texture) of their crystalline structure.
Note:
The common use of the term polycrystalline graphite for
polygranular graphite
is in line with this definition but may be inexact because usually all grains of polygranular graphite are polycrystalline themselves. Polycrystalline graphite can exhibit a random orientation, more or less preferred orientation, or a highly
oriented texture as in some pyrolytic graphites There is no sharp transition, however, between the typical polycrystalline texture
and the 'single crystal-like' texture of
highly oriented pyrolytic graphite
(HOPG).
Source:
PAC, 1995, 67, 473
(Recommended terminology for the description of carbon as a solid (IUPAC Recommendations
1995))
on page 500