diff --git a/python/core/qgseditformconfig.sip b/python/core/qgseditformconfig.sip
index f776fd62d92..ee8e13674db 100644
--- a/python/core/qgseditformconfig.sip
+++ b/python/core/qgseditformconfig.sip
@@ -482,7 +482,7 @@ class QgsEditFormConfig : QObject
      * @return the expression
      * @note added in QGIS 2.16
      */
-    QString constraint( int idx ) const;
+    QString expression( int idx ) const;
 
     /**
      * Set the constraint expression for a specific field
@@ -490,7 +490,7 @@ class QgsEditFormConfig : QObject
      * @param str the constraint expression
      * @note added in QGIS 2.16
      */
-    void setConstraint( int idx, const QString& str );
+    void setExpression( int idx, const QString& str );
 
     /**
      * Returns if the field at fieldidx should be treated as NOT NULL value
diff --git a/src/app/qgsattributetypedialog.cpp b/src/app/qgsattributetypedialog.cpp
index 2d7b09d608c..8b8cd2d1370 100644
--- a/src/app/qgsattributetypedialog.cpp
+++ b/src/app/qgsattributetypedialog.cpp
@@ -185,12 +185,12 @@ bool QgsAttributeTypeDialog::notNull() const
   return notNullCheckBox->isChecked();
 }
 
-void QgsAttributeTypeDialog::setConstraint( const QString &str )
+void QgsAttributeTypeDialog::setExpression( const QString &str )
 {
   constraintExpression->setField( str );
 }
 
-QString QgsAttributeTypeDialog::constraint() const
+QString QgsAttributeTypeDialog::expression() const
 {
   return constraintExpression->asExpression();
 }
diff --git a/src/app/qgsattributetypedialog.h b/src/app/qgsattributetypedialog.h
index b7b3b43ef3a..53c5e88bf1a 100644
--- a/src/app/qgsattributetypedialog.h
+++ b/src/app/qgsattributetypedialog.h
@@ -98,13 +98,13 @@ class APP_EXPORT QgsAttributeTypeDialog: public QDialog, private Ui::QgsAttribut
      * Getter for the constraint expression
      * @note added in QGIS 2.16
      */
-    QString constraint() const;
+    QString expression() const;
 
     /**
      * Setter for the constraint expression
      * @note added in QGIS 2.16
      */
-    void setConstraint( const QString &str );
+    void setExpression( const QString &str );
 
   private slots:
     /**
diff --git a/src/app/qgsfieldsproperties.cpp b/src/app/qgsfieldsproperties.cpp
index 92015291070..0b026992ea8 100644
--- a/src/app/qgsfieldsproperties.cpp
+++ b/src/app/qgsfieldsproperties.cpp
@@ -528,7 +528,7 @@ void QgsFieldsProperties::attributeTypeDialog()
   attributeTypeDialog.setFieldEditable( cfg.mEditable );
   attributeTypeDialog.setLabelOnTop( cfg.mLabelOnTop );
   attributeTypeDialog.setNotNull( cfg.mNotNull );
-  attributeTypeDialog.setConstraint( cfg.mConstraint );
+  attributeTypeDialog.setExpression( cfg.mConstraint );
 
   attributeTypeDialog.setWidgetV2Config( cfg.mEditorWidgetV2Config );
   attributeTypeDialog.setWidgetV2Type( cfg.mEditorWidgetV2Type );
@@ -539,7 +539,7 @@ void QgsFieldsProperties::attributeTypeDialog()
   cfg.mEditable = attributeTypeDialog.fieldEditable();
   cfg.mLabelOnTop = attributeTypeDialog.labelOnTop();
   cfg.mNotNull = attributeTypeDialog.notNull();
-  cfg.mConstraint = attributeTypeDialog.constraint();
+  cfg.mConstraint = attributeTypeDialog.expression();
 
   cfg.mEditorWidgetV2Type = attributeTypeDialog.editorWidgetV2Type();
   cfg.mEditorWidgetV2Config = attributeTypeDialog.editorWidgetV2Config();
@@ -913,7 +913,7 @@ void QgsFieldsProperties::apply()
     mLayer->editFormConfig()->setReadOnly( i, !cfg.mEditable );
     mLayer->editFormConfig()->setLabelOnTop( i, cfg.mLabelOnTop );
     mLayer->editFormConfig()->setNotNull( i, cfg.mNotNull );
-    mLayer->editFormConfig()->setConstraint( i, cfg.mConstraint );
+    mLayer->editFormConfig()->setExpression( i, cfg.mConstraint );
 
     mLayer->editFormConfig()->setWidgetType( idx, cfg.mEditorWidgetV2Type );
     mLayer->editFormConfig()->setWidgetConfig( idx, cfg.mEditorWidgetV2Config );
@@ -993,7 +993,7 @@ QgsFieldsProperties::FieldConfig::FieldConfig( QgsVectorLayer* layer, int idx )
                      && layer->fields().fieldOrigin( idx ) != QgsFields::OriginExpression;
   mLabelOnTop = layer->editFormConfig()->labelOnTop( idx );
   mNotNull = layer->editFormConfig()->notNull( idx );
-  mConstraint = layer->editFormConfig()->constraint( idx );
+  mConstraint = layer->editFormConfig()->expression( idx );
   mEditorWidgetV2Type = layer->editFormConfig()->widgetType( idx );
   mEditorWidgetV2Config = layer->editFormConfig()->widgetConfig( idx );
 
diff --git a/src/core/qgseditformconfig.cpp b/src/core/qgseditformconfig.cpp
index 1311624d1b8..8e153e22582 100644
--- a/src/core/qgseditformconfig.cpp
+++ b/src/core/qgseditformconfig.cpp
@@ -119,7 +119,7 @@ bool QgsEditFormConfig::labelOnTop( int idx ) const
     return false;
 }
 
-QString QgsEditFormConfig::constraint( int idx ) const
+QString QgsEditFormConfig::expression( int idx ) const
 {
   QString expr = "";
 
@@ -129,7 +129,7 @@ QString QgsEditFormConfig::constraint( int idx ) const
   return expr;
 }
 
-void QgsEditFormConfig::setConstraint( int idx, const QString& str )
+void QgsEditFormConfig::setExpression( int idx, const QString& str )
 {
   if ( idx >= 0 && idx < mFields.count() )
     mConstraints[ mFields.at( idx ).name()] = str;
diff --git a/src/core/qgseditformconfig.h b/src/core/qgseditformconfig.h
index 204600fc762..0371314fc03 100644
--- a/src/core/qgseditformconfig.h
+++ b/src/core/qgseditformconfig.h
@@ -518,7 +518,7 @@ class CORE_EXPORT QgsEditFormConfig : public QObject
      * @return the expression
      * @note added in QGIS 2.16
      */
-    QString constraint( int idx ) const;
+    QString expression( int idx ) const;
 
     /**
      * Set the constraint expression for a specific field
@@ -526,7 +526,7 @@ class CORE_EXPORT QgsEditFormConfig : public QObject
      * @param str the constraint expression
      * @note added in QGIS 2.16
      */
-    void setConstraint( int idx, const QString& str );
+    void setExpression( int idx, const QString& str );
 
     /**
      * Returns if the field at fieldidx should be treated as NOT NULL value
diff --git a/src/gui/editorwidgets/core/qgseditorwidgetregistry.cpp b/src/gui/editorwidgets/core/qgseditorwidgetregistry.cpp
index d6d9eef4368..769294dae1d 100644
--- a/src/gui/editorwidgets/core/qgseditorwidgetregistry.cpp
+++ b/src/gui/editorwidgets/core/qgseditorwidgetregistry.cpp
@@ -252,7 +252,7 @@ void QgsEditorWidgetRegistry::readMapLayer( QgsMapLayer* mapLayer, const QDomEle
       vectorLayer->editFormConfig()->setReadOnly( idx, ewv2CfgElem.attribute( "fieldEditable", "1" ) != "1" );
       vectorLayer->editFormConfig()->setLabelOnTop( idx, ewv2CfgElem.attribute( "labelOnTop", "0" ) == "1" );
       vectorLayer->editFormConfig()->setNotNull( idx, ewv2CfgElem.attribute( "notNull", "0" ) == "1" );
-      vectorLayer->editFormConfig()->setConstraint( idx, ewv2CfgElem.attribute( "constraint", "" ) );
+      vectorLayer->editFormConfig()->setExpression( idx, ewv2CfgElem.attribute( "constraint", "" ) );
 
       vectorLayer->editFormConfig()->setWidgetConfig( idx, cfg );
     }
@@ -311,7 +311,7 @@ void QgsEditorWidgetRegistry::writeMapLayer( QgsMapLayer* mapLayer, QDomElement&
       ewv2CfgElem.setAttribute( "fieldEditable", !vectorLayer->editFormConfig()->readOnly( idx ) );
       ewv2CfgElem.setAttribute( "labelOnTop", vectorLayer->editFormConfig()->labelOnTop( idx ) );
       ewv2CfgElem.setAttribute( "notNull", vectorLayer->editFormConfig()->notNull( idx ) );
-      ewv2CfgElem.setAttribute( "constraint", vectorLayer->editFormConfig()->constraint( idx ) );
+      ewv2CfgElem.setAttribute( "constraint", vectorLayer->editFormConfig()->expression( idx ) );
 
       mWidgetFactories[widgetType]->writeConfig( vectorLayer->editFormConfig()->widgetConfig( idx ), ewv2CfgElem, doc, vectorLayer, idx );
 
diff --git a/src/gui/editorwidgets/core/qgseditorwidgetwrapper.cpp b/src/gui/editorwidgets/core/qgseditorwidgetwrapper.cpp
index ef9959ad766..c076bf68223 100644
--- a/src/gui/editorwidgets/core/qgseditorwidgetwrapper.cpp
+++ b/src/gui/editorwidgets/core/qgseditorwidgetwrapper.cpp
@@ -107,7 +107,7 @@ void QgsEditorWidgetWrapper::updateConstraint( const QgsFeature &ft )
 {
   bool toEmit( false );
   QString errStr( "predicate is True" );
-  QString expression = layer()->editFormConfig()->constraint( mFieldIdx );
+  QString expression = layer()->editFormConfig()->expression( mFieldIdx );
   QVariant value = ft.attribute( mFieldIdx );
 
   if ( ! expression.isEmpty() )
diff --git a/src/gui/qgsattributeform.cpp b/src/gui/qgsattributeform.cpp
index 81d38ed6c08..62f73de2430 100644
--- a/src/gui/qgsattributeform.cpp
+++ b/src/gui/qgsattributeform.cpp
@@ -930,7 +930,7 @@ void QgsAttributeForm::constraintDependencies( QgsEditorWidgetWrapper *w,
       if ( name != ewwName )
       {
         // get expression and referencedColumns
-        QgsExpression expr = eww->layer()->editFormConfig()->constraint( eww->fieldIdx() );
+        QgsExpression expr = eww->layer()->editFormConfig()->expression( eww->fieldIdx() );
 
         Q_FOREACH ( const QString& colName, expr.referencedColumns() )
         {
diff --git a/tests/src/gui/testqgsattributeform.cpp b/tests/src/gui/testqgsattributeform.cpp
index 07e14669689..4451bed428f 100644
--- a/tests/src/gui/testqgsattributeform.cpp
+++ b/tests/src/gui/testqgsattributeform.cpp
@@ -81,7 +81,7 @@ void TestQgsAttributeForm::testFieldConstraint()
   QString invalidLabel = "col0<font color=\"red\">*</font>";
 
   // set constraint
-  layer->editFormConfig()->setConstraint( 0, "" );
+  layer->editFormConfig()->setExpression( 0, "" );
 
   // get wrapper
   QgsEditorWidgetWrapper *ww;
@@ -92,7 +92,7 @@ void TestQgsAttributeForm::testFieldConstraint()
   QCOMPARE( label->text(), QString( "col0" ) );
 
   // set a not null constraint
-  layer->editFormConfig()->setConstraint( 0, "col0 is not null" );
+  layer->editFormConfig()->setExpression( 0, "col0 is not null" );
 
   // set value to 1
   ww->setValue( 1 );
@@ -126,10 +126,10 @@ void TestQgsAttributeForm::testFieldMultiConstraints()
   ft.setAttribute( "col3", 3 );
 
   // set constraints for each field
-  layer->editFormConfig()->setConstraint( 0, "" );
-  layer->editFormConfig()->setConstraint( 1, "" );
-  layer->editFormConfig()->setConstraint( 2, "" );
-  layer->editFormConfig()->setConstraint( 3, "" );
+  layer->editFormConfig()->setExpression( 0, "" );
+  layer->editFormConfig()->setExpression( 1, "" );
+  layer->editFormConfig()->setExpression( 2, "" );
+  layer->editFormConfig()->setExpression( 3, "" );
 
   // build a form for this feature
   QgsAttributeForm form( layer );
@@ -160,10 +160,10 @@ void TestQgsAttributeForm::testFieldMultiConstraints()
   QCOMPARE( label3->text(), QString( "col3" ) );
 
   // update constraint
-  layer->editFormConfig()->setConstraint( 0, "col0 < (col1 * col2)" );
-  layer->editFormConfig()->setConstraint( 1, "" );
-  layer->editFormConfig()->setConstraint( 2, "" );
-  layer->editFormConfig()->setConstraint( 3, "col0 = 2" );
+  layer->editFormConfig()->setExpression( 0, "col0 < (col1 * col2)" );
+  layer->editFormConfig()->setExpression( 1, "" );
+  layer->editFormConfig()->setExpression( 2, "" );
+  layer->editFormConfig()->setExpression( 3, "col0 = 2" );
 
   // change value
   ww0->setValue( 2 ); // update col0
@@ -212,7 +212,7 @@ void TestQgsAttributeForm::testOKButtonStatus()
   QSignalSpy spy3( layer, SIGNAL( editingStopped() ) );
 
   // set constraint
-  layer->editFormConfig()->setConstraint( 0, "" );
+  layer->editFormConfig()->setExpression( 0, "" );
 
   // no constraint but layer not editable : OK button disabled
   QCOMPARE( layer->isEditable(), false );
@@ -225,12 +225,12 @@ void TestQgsAttributeForm::testOKButtonStatus()
   QCOMPARE( okButton->isEnabled(), true );
 
   // invalid constraint and editable layer : OK button disabled
-  layer->editFormConfig()->setConstraint( 0, "col0 = 0" );
+  layer->editFormConfig()->setExpression( 0, "col0 = 0" );
   ww->setValue( 1 );
   QCOMPARE( okButton->isEnabled(), false );
 
   // valid constraint and editable layer : OK button enabled
-  layer->editFormConfig()->setConstraint( 0, "col0 = 2" );
+  layer->editFormConfig()->setExpression( 0, "col0 = 2" );
   ww->setValue( 2 );
   QCOMPARE( okButton->isEnabled(), true );