diff --git a/src/internal/animations.js b/src/internal/animations.js
index fcbfba7521..ac14036724 100644
--- a/src/internal/animations.js
+++ b/src/internal/animations.js
@@ -28,7 +28,7 @@ export function animate(node, from, fn, params) {
 		if (css) {
 			if (delay) node.style.cssText = cssText;
 
-			name = create_rule({ a: 0, b: 1, delta: 1, duration }, easing, css);
+			name = create_rule({ a: 0, b: 1, d: 1, duration }, easing, css);
 
 			node.style.animation = (node.style.animation || '')
 				.split(', ')
diff --git a/src/internal/style_manager.js b/src/internal/style_manager.js
index 6af5c091ed..e4b15ad8d5 100644
--- a/src/internal/style_manager.js
+++ b/src/internal/style_manager.js
@@ -13,12 +13,12 @@ function hash(str) {
 	return hash >>> 0;
 }
 
-export function create_rule({ a, b, delta, duration }, ease, fn) {
+export function create_rule({ a, b, d, duration }, ease, fn) {
 	const step = 16.666 / duration;
 	let keyframes = '{\n';
 
 	for (let p = 0; p <= 1; p += step) {
-		const t = a + delta * ease(p);
+		const t = a + d * ease(p);
 		keyframes += p * 100 + `%{${fn(t, 1 - t)}}\n`;
 	}