diff --git a/tech/arduino_nano.wiki b/tech/arduino_nano.wiki
index 18c1540..399f4ef 100644
--- a/tech/arduino_nano.wiki
+++ b/tech/arduino_nano.wiki
@@ -66,7 +66,8 @@ To help with reading, the above info is in this table.
 === Interrupts ===
 
 Interrupts are the same as OS typical interrupts, controlled by the Interrupt
-lookup table. On this device the ILT is instead a control [[registers]]. 
+lookup table. On this device the ILT is instead a control [[registers]]. The
+code an interrupt calls is called an Interrupt Service Routine (ISR).
 
 The External Interrupt Control Regsiter (EICR 0x69) is a register that allows you to set
 the behaviour of the two built in interrupts. The Behaviour is set via setting