The modulus of rupture.
Number four on Michael Sorkin’s list of 250 things every architect should know refers to the strength of a structural element. How much force until the (toothpick, twin, log, beam) snaps? Various sizes of concrete, steel, different species of wood, etc are subjected to a test with a point load increasing until the structural member fails/snaps/ruptures. Various Youtube clips of various quality show how this type of testing takes place. As the Wood Database says “in practical terms, the number itself isn’t all that meaningful, but it becomes useful to use in comparison” [to other structural elements]. Most of architecture involves knowing a little bit about a lot of different things, jack of all trades and master of none. I’d file a ‘conversational’ knowledge of the modulus of rupture in this category (but what a name! It reminds me of the completely nonsensical Quantum of Solace title for Daniel Craig’s second Bond movie.)