diff --git a/src/ol/format/geojsonformat.js b/src/ol/format/geojsonformat.js
index f777f5d0f1..759a9e6531 100644
--- a/src/ol/format/geojsonformat.js
+++ b/src/ol/format/geojsonformat.js
@@ -449,7 +449,7 @@ ol.format.GeoJSON.prototype.readProjection = function(object) {
  *
  * @function
  * @param {ol.Feature} feature Feature.
- * @return {ArrayBuffer|Node|Object|string} Result.
+ * @return {ArrayBuffer|Node|Object|string} GeoJSON.
  * @todo api
  */
 ol.format.GeoJSON.prototype.writeFeature;
@@ -485,7 +485,7 @@ ol.format.GeoJSON.prototype.writeFeatureObject = function(feature) {
  *
  * @function
  * @param {Array.<ol.Feature>} features Features.
- * @return {ArrayBuffer|Node|Object|string} Result.
+ * @return {ArrayBuffer|Node|Object|string} GeoJSON.
  * @todo api
  */
 ol.format.GeoJSON.prototype.writeFeatures;
@@ -507,6 +507,17 @@ ol.format.GeoJSON.prototype.writeFeaturesObject = function(features) {
 };
 
 
+/**
+ * Encode a geometry as GeoJSON.
+ *
+ * @function
+ * @param {ol.geom.Geometry} geometry Geometry.
+ * @return {ArrayBuffer|Node|Object|string} GeoJSON.
+ * @todo api
+ */
+ol.format.GeoJSON.prototype.writeGeometry;
+
+
 /**
  * @inheritDoc
  */