diff --git a/concepts/type-checking/about.md b/concepts/type-checking/about.md
index d855cc9dda..0afed179a3 100644
--- a/concepts/type-checking/about.md
+++ b/concepts/type-checking/about.md
@@ -74,7 +74,7 @@ The `Array` class has a method called `Array.isArray()` that checks if its argum
 
 While `instanceof Array` will not work with an array created in a different realm such as an `iframe` in a webpage, `Array.isArray()` will.
 
-This is because the Array class has a different constructor in each realm, and each `iframe` has its own ream, meaning that the function in the prototype chain will be different, causing `instanceof Array` to fail.
+This is because the Array class has a different constructor in each realm, and each `iframe` has its own realm, meaning that the function in the prototype chain will be different, causing `instanceof Array` to fail.
 `Array.isArray()` is capable of ignoring this, and should always be used when possible.
 
 It can also survive false positives where an object isn't actually an `Array`, and merely has `Array` in its prototype chain.
diff --git a/concepts/type-checking/introduction.md b/concepts/type-checking/introduction.md
index d855cc9dda..0afed179a3 100644
--- a/concepts/type-checking/introduction.md
+++ b/concepts/type-checking/introduction.md
@@ -74,7 +74,7 @@ The `Array` class has a method called `Array.isArray()` that checks if its argum
 
 While `instanceof Array` will not work with an array created in a different realm such as an `iframe` in a webpage, `Array.isArray()` will.
 
-This is because the Array class has a different constructor in each realm, and each `iframe` has its own ream, meaning that the function in the prototype chain will be different, causing `instanceof Array` to fail.
+This is because the Array class has a different constructor in each realm, and each `iframe` has its own realm, meaning that the function in the prototype chain will be different, causing `instanceof Array` to fail.
 `Array.isArray()` is capable of ignoring this, and should always be used when possible.
 
 It can also survive false positives where an object isn't actually an `Array`, and merely has `Array` in its prototype chain.
diff --git a/exercises/concept/recycling-robot/.docs/introduction.md b/exercises/concept/recycling-robot/.docs/introduction.md
index 21f826324b..8628305814 100644
--- a/exercises/concept/recycling-robot/.docs/introduction.md
+++ b/exercises/concept/recycling-robot/.docs/introduction.md
@@ -74,7 +74,7 @@ The `Array` class has a method called `Array.isArray()` that checks if its argum
 
 While `instanceof Array` will not work with an array created in a different realm such as an `iframe` in a webpage, `Array.isArray()` will.
 
-This is because the Array class has a different constructor in each realm, and each `iframe` has its own ream, meaning that the function in the prototype chain will be different, causing `instanceof Array` to fail.
+This is because the Array class has a different constructor in each realm, and each `iframe` has its own realm, meaning that the function in the prototype chain will be different, causing `instanceof Array` to fail.
 `Array.isArray()` is capable of ignoring this, and should always be used when possible.
 
 It can also survive false positives where an object isn't actually an `Array`, and merely has `Array` in its prototype chain.