diff --git a/util.go b/util.go
index 9a3fb09..3911040 100644
--- a/util.go
+++ b/util.go
@@ -25,7 +25,7 @@ type State struct {
 	termios unix.Termios
 }
 
-// IsTerminal returns true if the given file descriptor is a terminal.
+// IsTerminal returns whether the given file descriptor is a terminal.
 func IsTerminal(fd int) bool {
 	_, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
 	return err == nil
diff --git a/util_plan9.go b/util_plan9.go
index 799f049..9317ac7 100644
--- a/util_plan9.go
+++ b/util_plan9.go
@@ -21,7 +21,7 @@ import (
 
 type State struct{}
 
-// IsTerminal returns true if the given file descriptor is a terminal.
+// IsTerminal returns whether the given file descriptor is a terminal.
 func IsTerminal(fd int) bool {
 	return false
 }
diff --git a/util_solaris.go b/util_solaris.go
index 9e41b9f..3d5f06a 100644
--- a/util_solaris.go
+++ b/util_solaris.go
@@ -17,7 +17,7 @@ type State struct {
 	termios unix.Termios
 }
 
-// IsTerminal returns true if the given file descriptor is a terminal.
+// IsTerminal returns whether the given file descriptor is a terminal.
 func IsTerminal(fd int) bool {
 	_, err := unix.IoctlGetTermio(fd, unix.TCGETA)
 	return err == nil
diff --git a/util_windows.go b/util_windows.go
index 8618955..6cb8a95 100644
--- a/util_windows.go
+++ b/util_windows.go
@@ -26,7 +26,7 @@ type State struct {
 	mode uint32
 }
 
-// IsTerminal returns true if the given file descriptor is a terminal.
+// IsTerminal returns whether the given file descriptor is a terminal.
 func IsTerminal(fd int) bool {
 	var st uint32
 	err := windows.GetConsoleMode(windows.Handle(fd), &st)