Definitions for "Grain Long"
The grain of paper is parallel to the long dimension of a sheet of paper. E.g. 45 x 64cm., long grain, indicates that the grain is traveling in the 64cm direction.
Grain running along the length, or long side, of a sheet of paper (23"x35"). Fibers line up parallel to the long side of the paper.
Indicating that the grain direction runs the larger dimension of a piece of material.