diff --git a/types/unist/index.d.ts b/types/unist/index.d.ts
index 121362a2ac..202b315250 100644
--- a/types/unist/index.d.ts
+++ b/types/unist/index.d.ts
@@ -34,7 +34,7 @@ export interface Position {
 
     // Start column at each index (plus start line) in the source region,
     // for elements that span multiple lines.
-    indent: number[];
+    indent?: number[];
 }
 
 // One place in a source file.