diff --git a/extras/source/wordbook/technical.dic b/extras/source/wordbook/technical.dic
index 3ee3281fcda9..b188eca131ba 100644
--- a/extras/source/wordbook/technical.dic
+++ b/extras/source/wordbook/technical.dic
@@ -77,6 +77,7 @@ FreeBSD
 Fujitsu
 gcc
 gcj
+GHz
 GIF
 gij
 GNOME
@@ -106,6 +107,7 @@ Jessie
 JPEG
 KDE
 Kerberos
+kHz
 Kubuntu
 Launchpad
 LDAP
@@ -122,6 +124,7 @@ MasterCard
 Math=
 Maverick
 Meerkat
+MHz
 Micro
 Microsoft=
 MicroStrategy=
@@ -203,6 +206,7 @@ Tahr
 TeliaSonera
 The
 Thunderbird
+THz
 Toshiba
 TrueType
 Trusty