diff --git a/3-terrarium/2-intro-to-css/README.md b/3-terrarium/2-intro-to-css/README.md
index b112c33c..cd87e707 100644
--- a/3-terrarium/2-intro-to-css/README.md
+++ b/3-terrarium/2-intro-to-css/README.md
@@ -15,7 +15,7 @@ CSS, or Cascading Style Sheets, solve an important problem of web development: h
 
 In this lesson, we're going to add styles to our online terrarium and learn more about several CSS concepts: the cascade, inheritance, and the use of selectors, positioning, and using CSS to build layouts. In the process we will layout the terrarium and create the actual terrarium itself.
 
-### Prequisite
+### Prerequisite
 
 You should have the HTML for your terrarium built and ready to be styled.