diff --git a/src/lib.rs b/src/lib.rs
index 488dec66..8fe898d3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -204,7 +204,8 @@ pub trait RoomEvent: Event {
     /// The unique identifier for the event.
     fn event_id(&self) -> &EventId;
 
-    /// Timestamp in milliseconds on originating homeserver when this event was sent.
+    /// Timestamp (milliseconds since the UNIX epoch) on originating homeserver when this event was
+    /// sent.
     fn origin_server_ts(&self) -> u64;
 
     /// The unique identifier for the room associated with this event.
diff --git a/src/macros.rs b/src/macros.rs
index ae98972e..6057dc4f 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -90,7 +90,8 @@ macro_rules! room_event {
             #[serde(rename = "type")]
             pub event_type: $crate::EventType,
 
-            /// Timestamp in milliseconds on originating homeserver when this event was sent.
+            /// Timestamp (milliseconds since the UNIX epoch) on originating homeserver when this
+            /// event was sent.
             pub origin_server_ts: u64,
 
             /// The unique identifier for the room associated with this event.