diff --git a/sphinx_doc_src/cmds/isatty.rst b/sphinx_doc_src/cmds/isatty.rst
index 69e940392..7edc65adc 100644
--- a/sphinx_doc_src/cmds/isatty.rst
+++ b/sphinx_doc_src/cmds/isatty.rst
@@ -1,7 +1,7 @@
 .. _cmd-isatty:
 
-isatty - test if a file descriptor is a tty.
-============================================
+isatty - test if a file descriptor is a terminal
+================================================
 
 Synopsis
 --------
@@ -13,11 +13,11 @@ Synopsis
 Description
 -----------
 
-``isatty`` tests if a file descriptor is a tty.
+``isatty`` tests if a file descriptor is a terminal (as opposed to a file). The name is derived from the system call of the same name, which for historical reasons refers to a teletypewriter (TTY).
 
 ``FILE DESCRIPTOR`` may be either the number of a file descriptor, or one of the strings ``stdin``, ``stdout``, or ``stderr``.
 
-If the specified file descriptor is a tty, the exit status of the command is zero. Otherwise, the exit status is non-zero. No messages are printed to standard error.
+If the specified file descriptor is a terminal device, the exit status of the command is zero. Otherwise, the exit status is non-zero. No messages are printed to standard error.
 
 
 Examples