diff --git a/Doc/lib/libthreading.tex b/Doc/lib/libthreading.tex
index b9f4e056c59..eb0985f0b63 100644
--- a/Doc/lib/libthreading.tex
+++ b/Doc/lib/libthreading.tex
@@ -369,7 +369,7 @@ than zero again, wake up that thread.
 \subsection{Event Objects \label{event-objects}}
 
 This is one of the simplest mechanisms for communication between
-threads: one thread signals an event and one or more other thread
+threads: one thread signals an event and one or more other threads
 are waiting for it.
 
 An event object manages an internal flag that can be set to true with