diff --git a/subjects/expandstr/README.md b/subjects/expandstr/README.md
index dd8d174d..33a69a1e 100644
--- a/subjects/expandstr/README.md
+++ b/subjects/expandstr/README.md
@@ -6,7 +6,7 @@ Write a program that takes a `string` and displays it with exactly three spaces
 
 The `string` will be followed by a newline (`'\n'`).
 
-A word is a sequence of alphanumerical characters.
+A word, in this exercise, is a sequence of visible characters.
 
 If the number of arguments is not 1, or if there are no word, the program displays nothing.