diff --git a/Bounce2/Bounce2.cpp b/Bounce2/Bounce2.cpp
index 3f15364..7f40970 100644
--- a/Bounce2/Bounce2.cpp
+++ b/Bounce2/Bounce2.cpp
@@ -27,7 +27,7 @@ void Bounce::attach(int pin) {
  if (digitalRead(pin)) {
    state = _BV(DEBOUNCED_STATE) | _BV(UNSTABLE_STATE);
  }
- #ifdef BOUNCE_LOCK-OUT
+ #ifdef BOUNCE_LOCK_OUT
  previous_millis = 0;
  #else
  previous_millis = millis();
@@ -41,7 +41,7 @@ void Bounce::interval(uint16_t interval_millis)
 
 bool Bounce::update()
 {
-#ifdef BOUNCE_LOCK-OUT
+#ifdef BOUNCE_LOCK_OUT
     state &= ~_BV(STATE_CHANGED);
 	// Ignore everything if we are locked out
 	if (millis() - previous_millis >= interval_millis) {
diff --git a/Bounce2/Bounce2.h b/Bounce2/Bounce2.h
index 59b5f13..df9402c 100644
--- a/Bounce2/Bounce2.h
+++ b/Bounce2/Bounce2.h
@@ -29,8 +29,12 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  Previous contributions by Eric Lowry, Jim Schimpf and Tom Harkaway
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
+#ifdef BOUNCE_LOCK
+#error You are using the invalid BOUNCE_LOCK-OUT define. Please update your sources to use BOUNCE_LOCK_OUT
+#endif
+
 // Uncomment the following line for "LOCK-OUT" debounce method
-//#define BOUNCE_LOCK-OUT
+//#define BOUNCE_LOCK_OUT
 
 
 #ifndef Bounce2_h