diff --git a/src/ol/View.js b/src/ol/View.js
index f7409fa3c2..79ab2e3080 100644
--- a/src/ol/View.js
+++ b/src/ol/View.js
@@ -2,7 +2,6 @@
  * @module ol/View
  */
 import BaseObject from './Object.js';
-import Units from './proj/Units.js';
 import ViewHint from './ViewHint.js';
 import ViewProperty from './ViewProperty.js';
 import {DEFAULT_TILE_SIZE} from './tilegrid/common.js';
@@ -2008,7 +2007,7 @@ export function createResolutionConstraint(options) {
     // calculate the default min and max resolution
     const size = !projExtent
       ? // use an extent that can fit the whole world if need be
-        (360 * METERS_PER_UNIT[Units.DEGREES]) / projection.getMetersPerUnit()
+        (360 * METERS_PER_UNIT.degrees) / projection.getMetersPerUnit()
       : Math.max(getWidth(projExtent), getHeight(projExtent));
 
     const defaultMaxResolution =
diff --git a/src/ol/control/ScaleLine.js b/src/ol/control/ScaleLine.js
index 031e746ec7..f303c43ecf 100644
--- a/src/ol/control/ScaleLine.js
+++ b/src/ol/control/ScaleLine.js
@@ -2,7 +2,6 @@
  * @module ol/control/ScaleLine
  */
 import Control from './Control.js';
-import ProjUnits from '../proj/Units.js';
 import {CLASS_UNSELECTABLE} from '../css.js';
 import {METERS_PER_UNIT, getPointResolution} from '../proj.js';
 import {assert} from '../asserts.js';
@@ -237,8 +236,7 @@ class ScaleLine extends Control {
     const center = viewState.center;
     const projection = viewState.projection;
     const units = this.getUnits();
-    const pointResolutionUnits =
-      units == 'degrees' ? ProjUnits.DEGREES : ProjUnits.METERS;
+    const pointResolutionUnits = units == 'degrees' ? 'degrees' : 'm';
     let pointResolution = getPointResolution(
       projection,
       viewState.resolution,
@@ -257,7 +255,7 @@ class ScaleLine extends Control {
     let nominalCount = minWidth * pointResolution;
     let suffix = '';
     if (units == 'degrees') {
-      const metersPerDegree = METERS_PER_UNIT[ProjUnits.DEGREES];
+      const metersPerDegree = METERS_PER_UNIT.degrees;
       nominalCount *= metersPerDegree;
       if (nominalCount < metersPerDegree / 60) {
         suffix = '\u2033'; // seconds
@@ -498,7 +496,7 @@ class ScaleLine extends Control {
       this.viewState_.projection,
       this.viewState_.resolution,
       this.viewState_.center,
-      ProjUnits.METERS
+      'm'
     );
     const dpi = this.dpi_ || DEFAULT_DPI;
     const inchesPerMeter = 1000 / 25.4;
diff --git a/src/ol/format/Feature.js b/src/ol/format/Feature.js
index d698e843c8..81f003794d 100644
--- a/src/ol/format/Feature.js
+++ b/src/ol/format/Feature.js
@@ -1,7 +1,6 @@
 /**
  * @module ol/format/Feature
  */
-import Units from '../proj/Units.js';
 import {abstract} from '../util.js';
 import {
   equivalent as equivalentProjection,
@@ -103,7 +102,7 @@ class FeatureFormat {
       if (
         opt_options.extent &&
         dataProjection &&
-        dataProjection.getUnits() === Units.TILE_PIXELS
+        dataProjection.getUnits() === 'tile-pixels'
       ) {
         dataProjection = getProjection(dataProjection);
         dataProjection.setWorldExtent(opt_options.extent);
diff --git a/src/ol/format/MVT.js b/src/ol/format/MVT.js
index 0133d7ae5c..849c98dcd8 100644
--- a/src/ol/format/MVT.js
+++ b/src/ol/format/MVT.js
@@ -13,7 +13,6 @@ import Point from '../geom/Point.js';
 import Polygon from '../geom/Polygon.js';
 import Projection from '../proj/Projection.js';
 import RenderFeature from '../render/Feature.js';
-import Units from '../proj/Units.js';
 import {assert} from '../asserts.js';
 import {get} from '../proj.js';
 import {inflateEnds} from '../geom/flat/orient.js';
@@ -52,7 +51,7 @@ class MVT extends FeatureFormat {
      */
     this.dataProjection = new Projection({
       code: '',
-      units: Units.TILE_PIXELS,
+      units: 'tile-pixels',
     });
 
     /**
diff --git a/src/ol/geom/Geometry.js b/src/ol/geom/Geometry.js
index cbaa005098..fef414eb40 100644
--- a/src/ol/geom/Geometry.js
+++ b/src/ol/geom/Geometry.js
@@ -2,7 +2,6 @@
  * @module ol/geom/Geometry
  */
 import BaseObject from '../Object.js';
-import Units from '../proj/Units.js';
 import {abstract} from '../util.js';
 import {
   compose as composeTransform,
@@ -310,7 +309,7 @@ class Geometry extends BaseObject {
     /** @type {import("../proj/Projection.js").default} */
     const sourceProj = getProjection(source);
     const transformFn =
-      sourceProj.getUnits() == Units.TILE_PIXELS
+      sourceProj.getUnits() == 'tile-pixels'
         ? function (inCoordinates, outCoordinates, stride) {
             const pixelExtent = sourceProj.getExtent();
             const projectedExtent = sourceProj.getWorldExtent();
diff --git a/src/ol/proj.js b/src/ol/proj.js
index 9cceb41fdc..50341ae95f 100644
--- a/src/ol/proj.js
+++ b/src/ol/proj.js
@@ -54,13 +54,13 @@
  * this.
  */
 import Projection from './proj/Projection.js';
-import Units, {METERS_PER_UNIT} from './proj/Units.js';
 import {
   PROJECTIONS as EPSG3857_PROJECTIONS,
   fromEPSG4326,
   toEPSG4326,
 } from './proj/epsg3857.js';
 import {PROJECTIONS as EPSG4326_PROJECTIONS} from './proj/epsg4326.js';
+import {METERS_PER_UNIT} from './proj/Units.js';
 import {
   add as addProj,
   clear as clearProj,
@@ -192,7 +192,7 @@ export function get(projectionLike) {
  * @param {ProjectionLike} projection The projection.
  * @param {number} resolution Nominal resolution in projection units.
  * @param {import("./coordinate.js").Coordinate} point Point to find adjusted resolution at.
- * @param {import("./proj/Units.js").default} [opt_units] Units to get the point resolution in.
+ * @param {import("./proj/Units.js").Units} [opt_units] Units to get the point resolution in.
  * Default is the projection's units.
  * @return {number} Point resolution.
  * @api
@@ -212,7 +212,7 @@ export function getPointResolution(projection, resolution, point, opt_units) {
     }
   } else {
     const units = projection.getUnits();
-    if ((units == Units.DEGREES && !opt_units) || opt_units == Units.DEGREES) {
+    if ((units == 'degrees' && !opt_units) || opt_units == 'degrees') {
       pointResolution = resolution;
     } else {
       // Estimate point resolution by transforming the center pixel to EPSG:4326,
@@ -222,7 +222,7 @@ export function getPointResolution(projection, resolution, point, opt_units) {
         projection,
         get('EPSG:4326')
       );
-      if (toEPSG4326 === identityTransform && units !== Units.DEGREES) {
+      if (toEPSG4326 === identityTransform && units !== 'degrees') {
         // no transform is available
         pointResolution = resolution * projection.getMetersPerUnit();
       } else {
diff --git a/src/ol/proj/Projection.js b/src/ol/proj/Projection.js
index 1724e2535b..1a4808c6dd 100644
--- a/src/ol/proj/Projection.js
+++ b/src/ol/proj/Projection.js
@@ -6,13 +6,13 @@ import {METERS_PER_UNIT} from './Units.js';
 /**
  * @typedef {Object} Options
  * @property {string} code The SRS identifier code, e.g. `EPSG:4326`.
- * @property {import("./Units.js").default|string} [units] Units. Required unless a
+ * @property {import("./Units.js").Units} [units] Units. Required unless a
  * proj4 projection is defined for `code`.
  * @property {import("../extent.js").Extent} [extent] The validity extent for the SRS.
  * @property {string} [axisOrientation='enu'] The axis orientation as specified in Proj4.
  * @property {boolean} [global=false] Whether the projection is valid for the whole globe.
  * @property {number} [metersPerUnit] The meters per unit for the SRS.
- * If not provided, the `units` are used to get the meters per unit from the {@link module:ol/proj/Units~METERS_PER_UNIT}
+ * If not provided, the `units` are used to get the meters per unit from the {@link METERS_PER_UNIT}
  * lookup table.
  * @property {import("../extent.js").Extent} [worldExtent] The world extent for the SRS.
  * @property {function(number, import("../coordinate.js").Coordinate):number} [getPointResolution]
@@ -65,9 +65,9 @@ class Projection {
      * `this.extent_` and `this.worldExtent_` must be configured properly for each
      * tile.
      * @private
-     * @type {import("./Units.js").default}
+     * @type {import("./Units.js").Units}
      */
-    this.units_ = /** @type {import("./Units.js").default} */ (options.units);
+    this.units_ = /** @type {import("./Units.js").Units} */ (options.units);
 
     /**
      * Validity extent of the projection in projected coordinates. For projections
@@ -153,7 +153,7 @@ class Projection {
 
   /**
    * Get the units of this projection.
-   * @return {import("./Units.js").default} Units.
+   * @return {import("./Units.js").Units} Units.
    * @api
    */
   getUnits() {
diff --git a/src/ol/proj/Units.js b/src/ol/proj/Units.js
index c8f13c3bed..e83d9df3ac 100644
--- a/src/ol/proj/Units.js
+++ b/src/ol/proj/Units.js
@@ -3,58 +3,20 @@
  */
 
 /**
- * Projection units: `'degrees'`, `'ft'`, `'m'`, `'pixels'`, `'tile-pixels'` or
- * `'us-ft'`.
- * @enum {string}
+ * @typedef {'radians' | 'degrees' | 'ft' | 'm' | 'pixels' | 'tile-pixels' | 'us-ft'} Units
+ * Projection units.
  */
-const Units = {
-  /**
-   * Radians
-   * @api
-   */
-  RADIANS: 'radians',
-  /**
-   * Degrees
-   * @api
-   */
-  DEGREES: 'degrees',
-  /**
-   * Feet
-   * @api
-   */
-  FEET: 'ft',
-  /**
-   * Meters
-   * @api
-   */
-  METERS: 'm',
-  /**
-   * Pixels
-   * @api
-   */
-  PIXELS: 'pixels',
-  /**
-   * Tile Pixels
-   * @api
-   */
-  TILE_PIXELS: 'tile-pixels',
-  /**
-   * US Feet
-   * @api
-   */
-  USFEET: 'us-ft',
-};
 
 /**
  * See http://duff.ess.washington.edu/data/raster/drg/docs/geotiff.txt
  * @type {Object<number, Units>}
  */
 const unitByCode = {
-  '9001': Units.METERS,
-  '9002': Units.FEET,
-  '9003': Units.USFEET,
-  '9101': Units.RADIANS,
-  '9102': Units.DEGREES,
+  '9001': 'm',
+  '9002': 'ft',
+  '9003': 'us-ft',
+  '9101': 'radians',
+  '9102': 'degrees',
 };
 
 /**
@@ -65,18 +27,26 @@ export function fromCode(code) {
   return unitByCode[code];
 }
 
+/**
+ * @typedef {Object} MetersPerUnitLookup
+ * @property {number} radians Radians
+ * @property {number} degrees Degrees
+ * @property {number} ft  Feet
+ * @property {number} m Meters
+ * @property {number} us-ft US feet
+ */
+
 /**
  * Meters per unit lookup table.
  * @const
- * @type {Object<Units, number>}
+ * @type {MetersPerUnitLookup}
  * @api
  */
-export const METERS_PER_UNIT = {};
-// use the radius of the Normal sphere
-METERS_PER_UNIT[Units.RADIANS] = 6370997 / (2 * Math.PI);
-METERS_PER_UNIT[Units.DEGREES] = (2 * Math.PI * 6370997) / 360;
-METERS_PER_UNIT[Units.FEET] = 0.3048;
-METERS_PER_UNIT[Units.METERS] = 1;
-METERS_PER_UNIT[Units.USFEET] = 1200 / 3937;
-
-export default Units;
+export const METERS_PER_UNIT = {
+  // use the radius of the Normal sphere
+  'radians': 6370997 / (2 * Math.PI),
+  'degrees': (2 * Math.PI * 6370997) / 360,
+  'ft': 0.3048,
+  'm': 1,
+  'us-ft': 1200 / 3937,
+};
diff --git a/src/ol/proj/epsg3857.js b/src/ol/proj/epsg3857.js
index 1ffcf96d65..6018eff23c 100644
--- a/src/ol/proj/epsg3857.js
+++ b/src/ol/proj/epsg3857.js
@@ -2,7 +2,6 @@
  * @module ol/proj/epsg3857
  */
 import Projection from './Projection.js';
-import Units from './Units.js';
 
 /**
  * Radius of WGS84 sphere
@@ -48,7 +47,7 @@ class EPSG3857Projection extends Projection {
   constructor(code) {
     super({
       code: code,
-      units: Units.METERS,
+      units: 'm',
       extent: EXTENT,
       global: true,
       worldExtent: WORLD_EXTENT,
diff --git a/src/ol/proj/epsg4326.js b/src/ol/proj/epsg4326.js
index 7bf303cdb0..72436a0a09 100644
--- a/src/ol/proj/epsg4326.js
+++ b/src/ol/proj/epsg4326.js
@@ -2,7 +2,6 @@
  * @module ol/proj/epsg4326
  */
 import Projection from './Projection.js';
-import Units from './Units.js';
 
 /**
  * Semi-major radius of the WGS84 ellipsoid.
@@ -42,7 +41,7 @@ class EPSG4326Projection extends Projection {
   constructor(code, opt_axisOrientation) {
     super({
       code: code,
-      units: Units.DEGREES,
+      units: 'degrees',
       extent: EXTENT,
       axisOrientation: opt_axisOrientation,
       global: true,
diff --git a/src/ol/proj/proj4.js b/src/ol/proj/proj4.js
index 7ce0ac56de..923a3bdf59 100644
--- a/src/ol/proj/proj4.js
+++ b/src/ol/proj/proj4.js
@@ -2,7 +2,6 @@
  * @module ol/proj/proj4
  */
 import Projection from './Projection.js';
-import Units from './Units.js';
 import {
   addCoordinateTransforms,
   addEquivalentProjections,
@@ -33,7 +32,7 @@ export function register(proj4) {
       const def = proj4.defs(code);
       let units = def.units;
       if (!units && def.projName === 'longlat') {
-        units = Units.DEGREES;
+        units = 'degrees';
       }
       addProjection(
         new Projection({
diff --git a/src/ol/tilegrid.js b/src/ol/tilegrid.js
index cdaab9c9fd..ef1856461c 100644
--- a/src/ol/tilegrid.js
+++ b/src/ol/tilegrid.js
@@ -2,7 +2,6 @@
  * @module ol/tilegrid
  */
 import TileGrid from './tilegrid/TileGrid.js';
-import Units from './proj/Units.js';
 import {DEFAULT_MAX_ZOOM, DEFAULT_TILE_SIZE} from './tilegrid/common.js';
 import {METERS_PER_UNIT, get as getProjection} from './proj.js';
 import {
@@ -176,7 +175,7 @@ export function extentFromProjection(projection) {
   let extent = projection.getExtent();
   if (!extent) {
     const half =
-      (180 * METERS_PER_UNIT[Units.DEGREES]) / projection.getMetersPerUnit();
+      (180 * METERS_PER_UNIT.degrees) / projection.getMetersPerUnit();
     extent = createOrUpdate(-half, -half, half, half);
   }
   return extent;
diff --git a/test/node/ol/proj.test.js b/test/node/ol/proj.test.js
index 6c85776de7..b3f1b1a7c9 100644
--- a/test/node/ol/proj.test.js
+++ b/test/node/ol/proj.test.js
@@ -1,5 +1,4 @@
 import Projection from '../../../src/ol/proj/Projection.js';
-import Units from '../../../src/ol/proj/Units.js';
 import View from '../../../src/ol/View.js';
 import expect from '../expect.js';
 import proj4 from 'proj4';
@@ -159,13 +158,13 @@ describe('ol/proj.js', function () {
   describe('fromUserResolution()', function () {
     it("adjusts a resolution for the user projection's units", function () {
       useGeographic();
-      const user = 1 / METERS_PER_UNIT['degrees'];
+      const user = 1 / METERS_PER_UNIT.degrees;
       const resolution = fromUserResolution(user, 'EPSG:3857');
       expect(resolution).to.roughlyEqual(1, 1e-9);
     });
 
     it('returns the original if no user projection is set', function () {
-      const user = METERS_PER_UNIT['meters'];
+      const user = METERS_PER_UNIT.meters;
       const resolution = fromUserResolution(user, 'EPSG:3857');
       expect(resolution).to.eql(user);
     });
@@ -176,11 +175,11 @@ describe('ol/proj.js', function () {
       useGeographic();
       const dest = 1;
       const resolution = toUserResolution(dest, 'EPSG:3857');
-      expect(resolution).to.eql(1 / METERS_PER_UNIT['degrees']);
+      expect(resolution).to.eql(1 / METERS_PER_UNIT.degrees);
     });
 
     it('returns the original if no user projection is set', function () {
-      const dest = METERS_PER_UNIT['degrees'];
+      const dest = METERS_PER_UNIT.degrees;
       const resolution = toUserResolution(dest, 'EPSG:3857');
       expect(resolution).to.eql(dest);
     });
@@ -435,7 +434,7 @@ describe('ol/proj.js', function () {
     it('returns the correct point resolution for EPSG:3857 with custom units', function () {
       let pointResolution = getPointResolution(
         'EPSG:3857',
-        METERS_PER_UNIT['degrees'],
+        METERS_PER_UNIT.degrees,
         [0, 0],
         'degrees'
       );
@@ -506,7 +505,7 @@ describe('ol/proj.js', function () {
       const proj = getProjection('EPSG:4258');
       expect(proj.getCode()).to.eql('EPSG:4258');
       expect(proj.getUnits()).to.eql('degrees');
-      expect(proj.getMetersPerUnit()).to.eql(METERS_PER_UNIT[Units.DEGREES]);
+      expect(proj.getMetersPerUnit()).to.eql(METERS_PER_UNIT.degrees);
 
       delete proj4.defs['EPSG:4258'];
     });
diff --git a/test/node/ol/tilegrid/TileGrid.test.js b/test/node/ol/tilegrid/TileGrid.test.js
index 438cd8df40..517736dbe0 100644
--- a/test/node/ol/tilegrid/TileGrid.test.js
+++ b/test/node/ol/tilegrid/TileGrid.test.js
@@ -444,7 +444,7 @@ describe('ol/tilegrid/TileGrid.js', function () {
       const grid = createForProjection(projection);
       const resolutions = grid.getResolutions();
       expect(resolutions[5]).to.be(
-        (360 * METERS_PER_UNIT['degrees']) / DEFAULT_TILE_SIZE / Math.pow(2, 5)
+        (360 * METERS_PER_UNIT.degrees) / DEFAULT_TILE_SIZE / Math.pow(2, 5)
       );
     });