diff --git a/modules/core_search_facets/src/Plugin/facets/facet_source/CoreNodeSearchFacetSource.php b/modules/core_search_facets/src/Plugin/facets/facet_source/CoreNodeSearchFacetSource.php
index 7bb815e..db8ba5c 100644
--- a/modules/core_search_facets/src/Plugin/facets/facet_source/CoreNodeSearchFacetSource.php
+++ b/modules/core_search_facets/src/Plugin/facets/facet_source/CoreNodeSearchFacetSource.php
@@ -358,7 +358,7 @@ public function calculateDependencies() {
   /**
    * {@inheritdoc}
    */
-  public function getFieldDefinitions() {
+  public function getDataDefinitions() {
     // Get and return an array field definitions.
   }
 
diff --git a/src/FacetSource/FacetSourcePluginBase.php b/src/FacetSource/FacetSourcePluginBase.php
index f64f021..2d24cb5 100644
--- a/src/FacetSource/FacetSourcePluginBase.php
+++ b/src/FacetSource/FacetSourcePluginBase.php
@@ -150,9 +150,10 @@ public function submitConfigurationForm(array &$form, FormStateInterface $form_s
   /**
    * {@inheritdoc}
    */
-  public function getFieldDefinition($field_name) {
-    if (isset($this->getFieldDefinitions()[$field_name])) {
-      return $this->getFieldDefinitions()[$field_name];
+  public function getDataDefinition($field_name) {
+    $dataDefinitions = $this->getDataDefinitions();
+    if (isset($dataDefinitions[$field_name])) {
+      return $dataDefinitions[$field_name];
     }
 
     throw new Exception("Field with name {$field_name} does not have a definition");
diff --git a/src/FacetSource/FacetSourcePluginInterface.php b/src/FacetSource/FacetSourcePluginInterface.php
index 1f52f2f..9c3cc86 100644
--- a/src/FacetSource/FacetSourcePluginInterface.php
+++ b/src/FacetSource/FacetSourcePluginInterface.php
@@ -103,13 +103,13 @@ public function getSearchKeys();
    *
    * @return \Drupal\Core\TypedData\DataDefinitionInterface[]
    */
-  public function getFieldDefinitions();
+  public function getDataDefinitions();
 
   /**
    * Returns one defined field from the facet source.
    *
    * @return \Drupal\Core\TypedData\DataDefinitionInterface
    */
-  public function getFieldDefinition($field_name);
+  public function getDataDefinition($field_name);
 
 }
diff --git a/src/Plugin/facets/facet_source/SearchApiDisplay.php b/src/Plugin/facets/facet_source/SearchApiDisplay.php
index 57fd912..c6f395f 100644
--- a/src/Plugin/facets/facet_source/SearchApiDisplay.php
+++ b/src/Plugin/facets/facet_source/SearchApiDisplay.php
@@ -323,7 +323,7 @@ public function getDisplay() {
   /**
    * {@inheritdoc}
    */
-  public function getFieldDefinitions() {
+  public function getDataDefinitions() {
     return array_map(function ($item) {
       /** @var \Drupal\search_api\Item\FieldInterface $item */
       return $item->getDataDefinition();
diff --git a/src/Plugin/facets/processor/TranslateEntityProcessor.php b/src/Plugin/facets/processor/TranslateEntityProcessor.php
index 410f302..dd48d6c 100644
--- a/src/Plugin/facets/processor/TranslateEntityProcessor.php
+++ b/src/Plugin/facets/processor/TranslateEntityProcessor.php
@@ -83,7 +83,7 @@ public function build(FacetInterface $facet, array $results) {
 
     /** @var \Drupal\Core\TypedData\DataDefinitionInterface $field_definition */
     $field_definition = $facet->getFacetSource()
-      ->getFieldDefinition($facet->getFieldIdentifier());
+      ->getDataDefinition($facet->getFieldIdentifier());
     if ($field_definition->getPropertyDefinition('entity') === NULL) {
       throw new InvalidProcessorException("Field doesn't have an entity definition, so this processor doesn't work.");
     }
diff --git a/tests/src/Kernel/Entity/FacetFacetSourceTest.php b/tests/src/Kernel/Entity/FacetFacetSourceTest.php
index 004a251..feb62d2 100644
--- a/tests/src/Kernel/Entity/FacetFacetSourceTest.php
+++ b/tests/src/Kernel/Entity/FacetFacetSourceTest.php
@@ -2,10 +2,12 @@
 
 namespace Drupal\Tests\facets\Kernel\Entity;
 
+use Drupal\Core\TypedData\DataDefinitionInterface;
 use Drupal\facets\Entity\Facet;
 use Drupal\facets\FacetSourceInterface;
 use Drupal\facets\Plugin\facets\facet_source\SearchApiDisplay;
 use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;
+use Drupal\facets\Exception\Exception;
 
 /**
  * Class FacetFacetSourceTest.
@@ -129,4 +131,29 @@ public function testQueryType() {
     $this->assertEquals('search_api_string', $aa);
   }
 
+  /**
+   * Test the data definitions.
+   *
+   * @covers \Drupal\facets\FacetSource\FacetSourcePluginInterface::getDataDefinitions
+   * @covers \Drupal\facets\FacetSource\FacetSourcePluginInterface::getDataDefinition
+   */
+  public function testDataDefinitions() {
+    // Create and configure facet.
+    $entity = new Facet([], 'facets_facet');
+    $display_name = 'search_api:views_page__search_api_test_view__page_1';
+    $entity->setFacetSourceId($display_name);
+
+    $dataDefinitions = $entity->getFacetSource()->getDataDefinitions();
+    $this->assertInternalType('array', $dataDefinitions);
+    $this->assertArrayHasKey('name', $dataDefinitions);
+    $this->assertArrayHasKey('type', $dataDefinitions);
+    $this->assertArrayHasKey('category', $dataDefinitions);
+
+    $this->assertInstanceOf(DataDefinitionInterface::class, $entity->getFacetSource()->getDataDefinition('id'));
+
+    // When giving a field that doesn't exist, we should throw an error.
+    $this->setExpectedException(Exception::class);
+    $entity->getFacetSource()->getDataDefinition('llama');
+  }
+
 }
diff --git a/tests/src/Unit/Plugin/processor/TranslateEntityProcessorTest.php b/tests/src/Unit/Plugin/processor/TranslateEntityProcessorTest.php
index 373c3f0..4670b03 100644
--- a/tests/src/Unit/Plugin/processor/TranslateEntityProcessorTest.php
+++ b/tests/src/Unit/Plugin/processor/TranslateEntityProcessorTest.php
@@ -75,25 +75,13 @@ protected function setUp() {
       ->method('getPropertyDefinition')
       ->willReturn($property_definition);
 
-    // Add the typed data definition to the search api field.
-    $field = $this->getMock(FieldInterface::class);
-    $field->expects($this->any())
-      ->method('getDataDefinition')
-      ->willReturn($data_definition);
-
-    // Add the search api field to the index.
-    $index = $this->getMock(IndexInterface::class);
-    $index->expects($this->any())
-      ->method('getField')
-      ->willReturn($field);
-
     // Create a search api based facet source and link the index to it.
     $facet_source = $this->getMockBuilder(SearchApiDisplay::class)
       ->disableOriginalConstructor()
       ->getMock();
     $facet_source->expects($this->any())
-      ->method('getIndex')
-      ->willReturn($index);
+      ->method('getDataDefinition')
+      ->willReturn($data_definition);
 
     // Create the actual facet.
     $this->facet = $this->getMockBuilder(Facet::class)