Electrical Code…
A drawing or other document provided by the manufacturer of the intrinsically safe or associated apparatus, or of the nonincendive field wiring apparatus or associated nonincendive field wiring apparatus, that details the allowed interconnections between the intrinsically safe and associated apparatus or between the nonincendive field wiring apparatus or associated nonincendive field wiring apparatus.
(National Electrical Code® 100-1)
(NT Note: Try reading this definition a few times… I’ll even hold your beer for you… I still don’t understand it… Good luck.)