diff --git a/base_classes/NXcharacterization.nxdl.xml b/base_classes/NXcharacterization.nxdl.xml
deleted file mode 100644
index 76c58ca10..000000000
--- a/base_classes/NXcharacterization.nxdl.xml
+++ /dev/null
@@ -1,80 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<?xml-stylesheet type="text/xsl" href="nxdlformat.xsl" ?>
-<!--
-# NeXus - Neutron and X-ray Common Data Format
-# 
-# Copyright (C) 2008-2017 NeXus International Advisory Committee (NIAC)
-# 
-# This library is free software; you can redistribute it and/or
-# modify it under the terms of the GNU Lesser General Public
-# License as published by the Free Software Foundation; either
-# version 3 of the License, or (at your option) any later version.
-#
-# This library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# Lesser General Public License for more details.
-#
-# You should have received a copy of the GNU Lesser General Public
-# License along with this library; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
-# For further information, see http://www.nexusformat.org
--->
-<definition xmlns="http://definition.nexusformat.org/nxdl/3.1" category="base"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://definition.nexusformat.org/nxdl/3.1 ../nxdl.xsd"
-	name="NXcharacterization" 
-	version="1.0"
-    type="group" extends="NXobject">
-
-	<doc>
-		legacy only - not intended for new use - may be removed in the future
-		
-		Note: This base class may be removed in future releases of NXDL.
-		If you have a use for this base class, please provide a description
-		of your intended use to the NIAC (nexus-committee@nexusformat.org).
-		
-		.. TODO: NXcharacterization needs proper documentation
-			<!-- see https://github.com/nexusformat/definitions/issues/177 -->
-			<!-- 
-				NOTE
-				====
-				The status of this class has been questioned.  
-				If you have a use for it, please provide
-				a definition of your intended use to  
-				NIAC <nexus-committee@nexusformat.org> 
-				so this class may be documented properly.
-				So far, it is referenced by these other classes:
-				* NXentry
-				* NXsubentry
-				* NXdetector
-			-->
-	</doc>
-  <!--
-	<attribute name="name">
-		<enumeration>
-			<item value="empty_environment" />
-			<item value="empty_environment_background" />
-			<item value="empty_container" />
-			<item value="empty_container_background" />
-			<item value="isotropic_scatterer" />
-			<item value="isotropic_scatterer_background" />
-			<item value="flood_image" />
-			<item value="dark_image" />
-			<item value="spatial_calibration_image" />
-		</enumeration>
-	</attribute>
--->
-	<attribute name="source">
-		<doc>If missing, the source file is the current file</doc>
-	</attribute>
-	<attribute name="location"/>
-	<attribute name="mime_type">
-		<doc>If missing, the source file is NAPI readable</doc>
-	</attribute>
-	<field name="definition">
-		<attribute name="version"/>
-		<attribute name="URL"/>
-	</field>
-</definition>
diff --git a/base_classes/NXdetector.nxdl.xml b/base_classes/NXdetector.nxdl.xml
index f94dd8935..ef8e249c0 100644
--- a/base_classes/NXdetector.nxdl.xml
+++ b/base_classes/NXdetector.nxdl.xml
@@ -468,11 +468,6 @@
 
   <group name="data_file" type="NXnote"/>
 
-  <group type="NXcharacterization" deprecated="use :ref:`NXcollection` instead">
-	<doc>
-		:see: https://github.com/nexusformat/definitions/issues/177
-	</doc>
-  </group>
   <group type="NXcollection">
 	<doc>
 		Use this group to provide other data related to this NXdetector group.
diff --git a/base_classes/NXentry.nxdl.xml b/base_classes/NXentry.nxdl.xml
index 8e788361d..7419b4bd2 100644
--- a/base_classes/NXentry.nxdl.xml
+++ b/base_classes/NXentry.nxdl.xml
@@ -205,7 +205,6 @@
 			</enumeration>
 		</attribute>
 	</group>
-	<group type="NXcharacterization" /><!-- TODO: consider using NXcollection instead, see https://github.com/nexusformat/definitions/issues/177-->
 	<group type="NXuser" />
 	<group type="NXsample" />
 	<group type="NXinstrument" />
diff --git a/base_classes/NXsubentry.nxdl.xml b/base_classes/NXsubentry.nxdl.xml
index 3b6dcddda..ec949cd00 100644
--- a/base_classes/NXsubentry.nxdl.xml
+++ b/base_classes/NXsubentry.nxdl.xml
@@ -174,7 +174,6 @@
 			</enumeration>
 		</attribute>
 	</group>
-	<group type="NXcharacterization" /><!-- TODO: consider using NXcollection instead, see https://github.com/nexusformat/definitions/issues/177-->
 	<group type="NXuser" />
 	<group type="NXsample" />
 	<group type="NXinstrument" />