diff --git a/index.d.cts b/index.d.cts
index 482dc89..b1911ca 100644
--- a/index.d.cts
+++ b/index.d.cts
@@ -359,7 +359,7 @@ declare namespace axios {
 
   type Milliseconds = number;
 
-  type AxiosAdapterName = 'fetch' | 'xhr' | 'http' | string;
+  type AxiosAdapterName = 'fetch' | 'xhr' | 'http' | (string & {});
 
   type AxiosAdapterConfig = AxiosAdapter | AxiosAdapterName;
 
diff --git a/index.d.ts b/index.d.ts
index 7989802..840fdcb 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -302,7 +302,7 @@ export interface AxiosProgressEvent {
 
 type Milliseconds = number;
 
-type AxiosAdapterName = 'fetch' | 'xhr' | 'http' | string;
+type AxiosAdapterName = 'fetch' | 'xhr' | 'http' | (string & {});
 
 type AxiosAdapterConfig = AxiosAdapter | AxiosAdapterName;