Module, m this indicates the tooth size and is the number of mm of pitch circle diameter (p.c.d.) per tooth. For gears to mesh, their modules must be equal. Gear ISO standards and design methods are now normally based on the module. EG a gear of module 3 has 16 teeth, its pitch circle diameter is: 3 x 16 = 48 mm.
I am curious as to which non-LEGO gears will mesh well with LEGO gears, but this is one of the more important numbers as far as figuring that out, yet I don't see the concrete number mentioned in any of the various LEGO gear descriptions/tutorials that show up when I search for it
To be very clear, all I am looking for is either single number, or an answer of "LEGO doesn't follow the mentioned Gear ISO standards".