diff --git a/src/ol/tilegrid/tilegrid.js b/src/ol/tilegrid/tilegrid.js
index 1f90552a56..b0aa02212a 100644
--- a/src/ol/tilegrid/tilegrid.js
+++ b/src/ol/tilegrid/tilegrid.js
@@ -115,18 +115,18 @@ ol.tilegrid.TileGrid.prototype.createTileCoordTransform = goog.abstractMethod;
 /**
  * @param {ol.TileCoord} tileCoord Tile coordinate.
  * @param {function(this: T, number, ol.TileRange): boolean} callback Callback.
- * @param {T=} opt_obj Object.
+ * @param {T=} opt_this The object to use as `this` in `callback`.
  * @param {ol.TileRange=} opt_tileRange Temporary ol.TileRange object.
  * @param {ol.Extent=} opt_extent Temporary ol.Extent object.
  * @return {boolean} Callback succeeded.
  * @template T
  */
 ol.tilegrid.TileGrid.prototype.forEachTileCoordParentTileRange =
-    function(tileCoord, callback, opt_obj, opt_tileRange, opt_extent) {
+    function(tileCoord, callback, opt_this, opt_tileRange, opt_extent) {
   var tileCoordExtent = this.getTileCoordExtent(tileCoord, opt_extent);
   var z = tileCoord.z - 1;
   while (z >= this.minZoom) {
-    if (callback.call(opt_obj, z,
+    if (callback.call(opt_this, z,
         this.getTileRangeForExtentAndZ(tileCoordExtent, z, opt_tileRange))) {
       return true;
     }
diff --git a/src/ol/tilegrid/xyztilegrid.js b/src/ol/tilegrid/xyztilegrid.js
index fba719b2ae..d3bdd82d6b 100644
--- a/src/ol/tilegrid/xyztilegrid.js
+++ b/src/ol/tilegrid/xyztilegrid.js
@@ -114,14 +114,14 @@ ol.tilegrid.XYZ.prototype.getTileCoordChildTileRange =
  * @inheritDoc
  */
 ol.tilegrid.XYZ.prototype.forEachTileCoordParentTileRange =
-    function(tileCoord, callback, opt_obj, opt_tileRange) {
+    function(tileCoord, callback, opt_this, opt_tileRange) {
   var tileRange = ol.TileRange.createOrUpdate(
       0, tileCoord.x, 0, tileCoord.y, opt_tileRange);
   var z;
   for (z = tileCoord.z - 1; z >= this.minZoom; --z) {
     tileRange.minX = tileRange.maxX >>= 1;
     tileRange.minY = tileRange.maxY >>= 1;
-    if (callback.call(opt_obj, z, tileRange)) {
+    if (callback.call(opt_this, z, tileRange)) {
       return true;
     }
   }