diff --git a/unix/platform.h b/unix/platform.h
index 670febd7..413a0282 100644
--- a/unix/platform.h
+++ b/unix/platform.h
@@ -394,12 +394,22 @@ void setup_fd_socket(Socket *s, int infd, int outfd, int inerrfd);
 void fd_socket_set_psb_prefix(Socket *s, const char *prefix);
 
 /*
- * Default font setting, which can vary depending on NOT_X_WINDOWS.
+ * Default font settings. We have a default font for each of
+ * client-side and server-side, so that we can use one of each as a
+ * fallback, and we also have a single overall default which goes into
+ * Conf to populate the initial state of Default Settings.
+ *
+ * The overall default varies depending on NOT_X_WINDOWS: if X is
+ * available then the default is xterm's traditional "fixed", but if
+ * it's not, so that only client-side fonts can be used at all, we
+ * switch to a client-side default.
  */
+#define DEFAULT_GTK_CLIENT_FONT "client:Monospace 12"
+#define DEFAULT_GTK_SERVER_FONT "server:fixed"
 #ifdef NOT_X_WINDOWS
-#define DEFAULT_GTK_FONT "client:Monospace 12"
+#define DEFAULT_GTK_FONT DEFAULT_GTK_CLIENT_FONT
 #else
-#define DEFAULT_GTK_FONT "server:fixed"
+#define DEFAULT_GTK_FONT DEFAULT_GTK_SERVER_FONT
 #endif
 
 /*
diff --git a/unix/window.c b/unix/window.c
index 3316f996..7302dc2c 100644
--- a/unix/window.c
+++ b/unix/window.c
@@ -5361,8 +5361,8 @@ void new_session_window(Conf *conf, const char *geometry_string)
             goto fonts_ok;
 
         static const char *const fallbacks[] = {
-            "client:Monospace 10",
-            "server:fixed",
+            DEFAULT_GTK_CLIENT_FONT,
+            DEFAULT_GTK_SERVER_FONT,
         };
         for (size_t i = 0; i < lenof(fallbacks); i++) {
             Conf *fallback_conf = conf_new();