diff --git a/doc/api/cluster.md b/doc/api/cluster.md
index c12c9758b94c9f..62412da0bf51ae 100644
--- a/doc/api/cluster.md
+++ b/doc/api/cluster.md
@@ -415,13 +415,13 @@ if (cluster.isMaster) {
 }
 ```
 
-### `worker.kill([signal='SIGTERM'])`
+### `worker.kill([signal])`
 <!-- YAML
 added: v0.9.12
 -->
 
 * `signal` {string} Name of the kill signal to send to the worker
-  process.
+  process. **Default**: `'SIGTERM'`
 
 This function will kill the worker. In the master, it does this by disconnecting
 the `worker.process`, and once disconnected, killing with `signal`. In the