diff --git a/source/chapter2/21_Protocols.md b/source/chapter2/21_Protocols.md
index 77665dab..c8c4997d 100644
--- a/source/chapter2/21_Protocols.md
+++ b/source/chapter2/21_Protocols.md
@@ -84,7 +84,7 @@
 	class Starship: FullyNamed {
 		var prefix: String?
 		var name: String
-		init(name: String, prefix: Stirng? = nil ) {
+		init(name: String, prefix: String? = nil ) {
 			self.anme = name
 			self.prefix = prefix
 		}