diff --git a/latex.html.markdown b/latex.html.markdown
index c980f5e5..e8bc6064 100644
--- a/latex.html.markdown
+++ b/latex.html.markdown
@@ -141,7 +141,7 @@ Operators are essential parts of a mathematical document:
 trigonometric functions ($\sin$, $\cos$, $\tan$),
 logarithms and exponentials ($\log$, $\exp$),
 limits ($\lim$), etc.\ 
-have per-defined LaTeX commands.
+have pre-defined LaTeX commands.
 Let's write an equation to see how it's done:
 $\cos(2\theta) = \cos^{2}(\theta) - \sin^{2}(\theta)$