diff --git a/sonoff/language/zh-TW.h b/sonoff/language/zh-TW.h
index 61fa90d4d..d48cec44a 100644
--- a/sonoff/language/zh-TW.h
+++ b/sonoff/language/zh-TW.h
@@ -110,6 +110,7 @@
 #define D_IP_ADDRESS "IP地址"
 #define D_LIGHT "燈"
 #define D_LWT "LWT"
+#define D_MMHG "mmHg"
 #define D_MODULE "模組"
 #define D_MQTT "MQTT"
 #define D_MULTI_PRESS "多次按鍵"