diff --git a/src/idl/nanopb/event.proto b/src/idl/nanopb/event.proto
index 08115bad..7883efe0 100644
--- a/src/idl/nanopb/event.proto
+++ b/src/idl/nanopb/event.proto
@@ -38,7 +38,7 @@ message Event {
   required Type type = 4; /// string types are more sanely extensible, but enum types would be more typo resistant and smaller message size
   required uint32 time_utc = 5; /// when the event occurred (unix epoch seconds)
   required sint32 utc_to_local = 6; /// time_utc + utc_to_local = time_local. sint32 stores neg number efficiently. need to recast before adding to time_utc, but saves storage
-  optional uint32 created_time_utc = 7; /// events may be created at times other than their occurance
+  optional uint32 created_time_utc = 7; /// events may be created at times other than their occurrence
   optional uint32 duration = 8;  /// in same units as time_utc (sec)
   optional LocationInfo location = 9;
   optional ActivitySession activity_session = 10;