diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 629a32f1b63e7d..5b2c2e0d0f2d03 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -4869,7 +4869,7 @@ Random numbers
 
 .. function:: urandom(size)
 
-   Return a string of *size* random bytes suitable for cryptographic use.
+   Return a bytestring of *size* random bytes suitable for cryptographic use.
 
    This function returns random bytes from an OS-specific randomness source.  The
    returned data should be unpredictable enough for cryptographic applications,