diff --git a/docs/data-fetching.md b/docs/data-fetching.md
index 4bc0cfb..346cd9a 100644
--- a/docs/data-fetching.md
+++ b/docs/data-fetching.md
@@ -103,22 +103,22 @@ for a field you simply override this default resolver.
 **graphql-php** provides following default field resolver:
 ```php
 <?php
-function defaultFieldResolver($source, $args, $context, \GraphQL\Type\Definition\ResolveInfo $info)
+function defaultFieldResolver($rootValue, $args, $context, \GraphQL\Type\Definition\ResolveInfo $info)
 {
     $fieldName = $info->fieldName;
-    $property = null;
+    $property  = null;
 
-    if (is_array($source) || $source instanceof \ArrayAccess) {
-        if (isset($source[$fieldName])) {
-            $property = $source[$fieldName];
+    if (is_array($rootValue) || $rootValue instanceof ArrayAccess) {
+        if (isset($rootValue[$fieldName])) {
+            $property = $rootValue[$fieldName];
         }
-    } else if (is_object($source)) {
-        if (isset($source->{$fieldName})) {
-            $property = $source->{$fieldName};
+    } elseif (is_object($rootValue)) {
+        if (isset($rootValue->{$fieldName})) {
+            $property = $rootValue->{$fieldName};
         }
     }
 
-    return $property instanceof Closure ? $property($source, $args, $context, $info) : $property;
+    return $property instanceof Closure ? $property($rootValue, $args, $context, $info) : $property;
 }
 ```
 
diff --git a/docs/reference.md b/docs/reference.md
index 7ea7709..c9f4a11 100644
--- a/docs/reference.md
+++ b/docs/reference.md
@@ -33,7 +33,7 @@ See [related documentation](executing-queries.md).
  * fieldResolver:
  *    A resolver function to use when one is not provided by the schema.
  *    If not provided, the default field resolver is used (which looks for a
- *    value on the source value with the field's name).
+ *    value on the root value with the field's name).
  * validationRules:
  *    A set of rules for query validation step. Default value is all available rules.
  *    Empty array would allow to skip query validation (may be convenient for persisted
diff --git a/src/Executor/ExecutionContext.php b/src/Executor/ExecutionContext.php
index 3de1a2e..6bd7318 100644
--- a/src/Executor/ExecutionContext.php
+++ b/src/Executor/ExecutionContext.php
@@ -50,7 +50,7 @@ class ExecutionContext
     public function __construct(
         $schema,
         $fragments,
-        $root,
+        $rootValue,
         $contextValue,
         $operation,
         $variables,
@@ -60,7 +60,7 @@ class ExecutionContext
     ) {
         $this->schema         = $schema;
         $this->fragments      = $fragments;
-        $this->rootValue      = $root;
+        $this->rootValue      = $rootValue;
         $this->contextValue   = $contextValue;
         $this->operation      = $operation;
         $this->variableValues = $variables;
diff --git a/src/Executor/Executor.php b/src/Executor/Executor.php
index 30ccad4..cc76e4c 100644
--- a/src/Executor/Executor.php
+++ b/src/Executor/Executor.php
@@ -157,31 +157,31 @@ class Executor
 
     /**
      * If a resolve function is not given, then a default resolve behavior is used
-     * which takes the property of the source object of the same name as the field
+     * which takes the property of the root value of the same name as the field
      * and returns it as the result, or if it's a function, returns the result
      * of calling that function while passing along args and context.
      *
-     * @param mixed      $source
+     * @param mixed      $rootValue
      * @param mixed[]    $args
      * @param mixed|null $context
      *
      * @return mixed|null
      */
-    public static function defaultFieldResolver($source, $args, $context, ResolveInfo $info)
+    public static function defaultFieldResolver($rootValue, $args, $context, ResolveInfo $info)
     {
         $fieldName = $info->fieldName;
         $property  = null;
 
-        if (is_array($source) || $source instanceof ArrayAccess) {
-            if (isset($source[$fieldName])) {
-                $property = $source[$fieldName];
+        if (is_array($rootValue) || $rootValue instanceof ArrayAccess) {
+            if (isset($rootValue[$fieldName])) {
+                $property = $rootValue[$fieldName];
             }
-        } elseif (is_object($source)) {
-            if (isset($source->{$fieldName})) {
-                $property = $source->{$fieldName};
+        } elseif (is_object($rootValue)) {
+            if (isset($rootValue->{$fieldName})) {
+                $property = $rootValue->{$fieldName};
             }
         }
 
-        return $property instanceof Closure ? $property($source, $args, $context, $info) : $property;
+        return $property instanceof Closure ? $property($rootValue, $args, $context, $info) : $property;
     }
 }
diff --git a/src/Executor/ReferenceExecutor.php b/src/Executor/ReferenceExecutor.php
index 6e35f7c..6c4a00c 100644
--- a/src/Executor/ReferenceExecutor.php
+++ b/src/Executor/ReferenceExecutor.php
@@ -237,7 +237,7 @@ class ReferenceExecutor implements ExecutorImplementation
     /**
      * Implements the "Evaluating operations" section of the spec.
      *
-     * @param  mixed[] $rootValue
+     * @param  mixed $rootValue
      *
      * @return Promise|stdClass|mixed[]
      */
@@ -463,21 +463,21 @@ class ReferenceExecutor implements ExecutorImplementation
      * Implements the "Evaluating selection sets" section of the spec
      * for "write" mode.
      *
-     * @param mixed[]     $sourceValue
+     * @param mixed       $rootValue
      * @param mixed[]     $path
      * @param ArrayObject $fields
      *
      * @return Promise|stdClass|mixed[]
      */
-    private function executeFieldsSerially(ObjectType $parentType, $sourceValue, $path, $fields)
+    private function executeFieldsSerially(ObjectType $parentType, $rootValue, $path, $fields)
     {
         $result = $this->promiseReduce(
             array_keys($fields->getArrayCopy()),
-            function ($results, $responseName) use ($path, $parentType, $sourceValue, $fields) {
+            function ($results, $responseName) use ($path, $parentType, $rootValue, $fields) {
                 $fieldNodes  = $fields[$responseName];
                 $fieldPath   = $path;
                 $fieldPath[] = $responseName;
-                $result      = $this->resolveField($parentType, $sourceValue, $fieldNodes, $fieldPath);
+                $result      = $this->resolveField($parentType, $rootValue, $fieldNodes, $fieldPath);
                 if ($result === self::$UNDEFINED) {
                     return $results;
                 }
@@ -505,18 +505,19 @@ class ReferenceExecutor implements ExecutorImplementation
     }
 
     /**
-     * Resolves the field on the given source object. In particular, this
-     * figures out the value that the field returns by calling its resolve function,
-     * then calls completeValue to complete promises, serialize scalars, or execute
-     * the sub-selection-set for objects.
+     * Resolves the field on the given root value.
      *
-     * @param object|null $source
+     * In particular, this figures out the value that the field returns
+     * by calling its resolve function, then calls completeValue to complete promises,
+     * serialize scalars, or execute the sub-selection-set for objects.
+     *
+     * @param mixed       $rootValue
      * @param FieldNode[] $fieldNodes
      * @param mixed[]     $path
      *
      * @return mixed[]|Exception|mixed|null
      */
-    private function resolveField(ObjectType $parentType, $source, $fieldNodes, $path)
+    private function resolveField(ObjectType $parentType, $rootValue, $fieldNodes, $path)
     {
         $exeContext = $this->exeContext;
         $fieldNode  = $fieldNodes[0];
@@ -557,7 +558,7 @@ class ReferenceExecutor implements ExecutorImplementation
             $fieldDef,
             $fieldNode,
             $resolveFn,
-            $source,
+            $rootValue,
             $context,
             $info
         );
@@ -614,13 +615,13 @@ class ReferenceExecutor implements ExecutorImplementation
      * @param FieldDefinition $fieldDef
      * @param FieldNode       $fieldNode
      * @param callable        $resolveFn
-     * @param mixed           $source
+     * @param mixed           $rootValue
      * @param mixed           $context
      * @param ResolveInfo     $info
      *
      * @return Throwable|Promise|mixed
      */
-    private function resolveOrError($fieldDef, $fieldNode, $resolveFn, $source, $context, $info)
+    private function resolveOrError($fieldDef, $fieldNode, $resolveFn, $rootValue, $context, $info)
     {
         try {
             // Build hash of arguments from the field.arguments AST, using the
@@ -631,7 +632,7 @@ class ReferenceExecutor implements ExecutorImplementation
                 $this->exeContext->variableValues
             );
 
-            return $resolveFn($source, $args, $context, $info);
+            return $resolveFn($rootValue, $args, $context, $info);
         } catch (Exception $error) {
             return $error;
         } catch (Throwable $error) {