diff --git a/sonoff/language/pl-PL.h b/sonoff/language/pl-PL.h
index 686f5cc76..df4853066 100644
--- a/sonoff/language/pl-PL.h
+++ b/sonoff/language/pl-PL.h
@@ -110,6 +110,7 @@
 #define D_IP_ADDRESS "Adres IP"
 #define D_LIGHT "Światło"
 #define D_LWT "LWT"
+#define D_MMHG "mmHg"
 #define D_MODULE "Moduł"
 #define D_MQTT "MQTT"
 #define D_MULTI_PRESS "wielokrotne-naciśnięcie"