The most precious tool is a word. Here is a list of how to speak about mail. You even get it for free.
Mail is arranged in rows. Often that is expressed schematically in artworks. In a row, the rings overlap like fallen domino bricks. Some meshes consist of two types of rings: riveted and solid rings. Riveted rings sit on different rows than solid rings.
Columns are lines of rings in 90° direction to rows. Along columns, the rings do not overlap like fallen domino bricks. They just barely touch.
The 4in1-weave of mail meshes shows different properties depending on how it is hung. One way is bringing the hung mesh to contract. This is named closed hang. Rows are running horizontally.
Turned by 90°, the mesh opens and fans out. That is called open hang. Row are running vertically. These terms have been in use. We could not backtrace to who used it first.
Rings tilt one way or another. Sebastian Voelk has established a vocabulary of naming them a- and b-tilt. a-tilt means that the ring’s left side is elevated and thus more visible. b-tilt means that the ring’s right side is elevated. The mesh must be looked at with rows running horizontally.
One can make the association easy to remember: The most visible part of the ring looks like a half-circle. That half-circle either reminds of the belly shape in the letter a or b. Rings in a row have the same tilt.