diff --git a/source/basic.tex b/source/basic.tex
index 2a717380e2..3b466cc94c 100644
--- a/source/basic.tex
+++ b/source/basic.tex
@@ -7376,7 +7376,7 @@
 \end{note}
 
 \pnum
-There is an observablecheckpoint\iref{intro.abstract} $C$
+There is an observable checkpoint\iref{intro.abstract} $C$
 that happens before $A$
 such that any other operation $O$
 that happens before $A$