diff --git a/locales/pt-PT/browser/browser/preferences/zen-preferences.ftl b/locales/pt-PT/browser/browser/preferences/zen-preferences.ftl
index aff4680ae..a18318154 100644
--- a/locales/pt-PT/browser/browser/preferences/zen-preferences.ftl
+++ b/locales/pt-PT/browser/browser/preferences/zen-preferences.ftl
@@ -44,6 +44,8 @@ category-zen-workspaces =
 pane-settings-workspaces-title = Espaços de Trabalho
 zen-tabs-unloader-enabled = 
     .label = Habilitar a Hibernação de Separadores
+zen-tabs-close-on-back-with-no-history = 
+    .label = Close tab and switch to its owner tab (or most recently used tab) when going back with no history
 zen-look-and-feel-compact-toolbar-themed = 
     .label = Usar fundo temático para a barra de ferramentas compacta
 zen-workspace-continue-where-left-off =