Would be extremely useful to get an explanation of what 3M means is the "Z-axis" of the tape. Along the tape plane? Across the tape plane? Through the tape pla

Would be extremely useful to get an explanation of what 3M means is the "Z-axis" of the tape. Along the tape plane? Across the tape plane? Through the tape plane? I can see uses for all, but how you'd apply it would certainly differ if depending on which one is Z....