Node A6 · Acronym decoder
N2
N-squared diagram
What it actually means
An N×N matrix with system elements on the diagonal and their interfaces in the off-diagonal cells — outputs read across the row, inputs down the column. It guarantees every possible interface gets consciously considered (even if the answer is "none"), which is exactly the discipline interface definition needs early in architecture work.
Where you'll meet it
Architecture definition and interface management, often as the precursor to the ICD list.