diff --git a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/PredefinedObjectMetadata.java b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/ObjectMetadata.java
similarity index 51%
rename from data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/PredefinedObjectMetadata.java
rename to data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/ObjectMetadata.java
index 3e24c07ddd..c8bdec2062 100644
--- a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/PredefinedObjectMetadata.java
+++ b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/ObjectMetadata.java
@@ -6,12 +6,12 @@
 package org.opensearch.dataprepper.plugins.sink.s3;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
-public class PredefinedObjectMetadata {
-    @JsonProperty("number_of_objects")
-    private String numberOfObjects;
+public class ObjectMetadata {
+    @JsonProperty("number_of_events_key")
+    private String numberOfEventsKey;
 
-    public String getNumberOfObjects() {
-        return numberOfObjects;
+    public String getNumberOfEventsKey() {
+        return numberOfEventsKey;
     }
 
 }
diff --git a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/S3SinkConfig.java b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/S3SinkConfig.java
index 9e690d739a..6289585113 100644
--- a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/S3SinkConfig.java
+++ b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/S3SinkConfig.java
@@ -43,8 +43,8 @@ public class S3SinkConfig {
     @JsonProperty("bucket_selector")
     private PluginModel bucketSelector;
 
-    @JsonProperty("predefined_object_metadata")
-    private PredefinedObjectMetadata predefinedObjectMetadata;
+    @JsonProperty("object_metadata")
+    private ObjectMetadata objectMetadata;
 
     @AssertTrue(message = "You may not use both bucket and bucket_selector together in one S3 sink.")
     private boolean isValidBucketConfig() {
@@ -142,8 +142,8 @@ public ObjectKeyOptions getObjectKeyOptions() {
         return objectKeyOptions;
     }
 
-    public PredefinedObjectMetadata getPredefinedObjectMetadata() {
-        return predefinedObjectMetadata;
+    public ObjectMetadata getObjectMetadata() {
+        return objectMetadata;
     }
 
     /**
diff --git a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifier.java b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifier.java
index 52fa2578fd..8cb45b4b90 100644
--- a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifier.java
+++ b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifier.java
@@ -5,7 +5,7 @@
 
 package org.opensearch.dataprepper.plugins.sink.s3.grouping;
 
-import org.opensearch.dataprepper.plugins.sink.s3.PredefinedObjectMetadata;
+import org.opensearch.dataprepper.plugins.sink.s3.ObjectMetadata;
 import java.util.Map;
 import java.util.Objects;
 
@@ -13,16 +13,16 @@ class S3GroupIdentifier {
     private final Map<String, Object> groupIdentifierHash;
     private final String groupIdentifierFullObjectKey;
 
-    private final PredefinedObjectMetadata predefinedObjectMetadata;
+    private final ObjectMetadata objectMetadata;
     private final String fullBucketName;
 
     public S3GroupIdentifier(final Map<String, Object> groupIdentifierHash,
                              final String groupIdentifierFullObjectKey,
-                             final PredefinedObjectMetadata predefineObjectMetadata,
+                             final ObjectMetadata objectMetadata,
                              final String fullBucketName) {
         this.groupIdentifierHash = groupIdentifierHash;
         this.groupIdentifierFullObjectKey = groupIdentifierFullObjectKey;
-        this.predefinedObjectMetadata = predefineObjectMetadata;
+        this.objectMetadata = objectMetadata;
         this.fullBucketName = fullBucketName;
     }
 
@@ -43,6 +43,6 @@ public int hashCode() {
 
     public Map<String, Object> getGroupIdentifierHash() { return groupIdentifierHash; }
 
-    public Map<String, String> getMetadata(int eventCount) { return predefinedObjectMetadata != null ? Map.of(predefinedObjectMetadata.getNumberOfObjects(), Integer.toString(eventCount)) : null; }
+    public Map<String, String> getMetadata(int eventCount) { return objectMetadata != null ? Map.of(objectMetadata.getNumberOfEventsKey(), Integer.toString(eventCount)) : null; }
     public String getFullBucketName() { return fullBucketName; }
 }
diff --git a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifierFactory.java b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifierFactory.java
index 89315d95a1..d12d237f5f 100644
--- a/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifierFactory.java
+++ b/data-prepper-plugins/s3-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/s3/grouping/S3GroupIdentifierFactory.java
@@ -70,6 +70,6 @@ public S3GroupIdentifier getS3GroupIdentifierForEvent(final Event event) {
         }
 
 
-        return new S3GroupIdentifier(groupIdentificationHash, fullObjectKey, s3SinkConfig.getPredefinedObjectMetadata(), fullBucketName);
+        return new S3GroupIdentifier(groupIdentificationHash, fullObjectKey, s3SinkConfig.getObjectMetadata(), fullBucketName);
     }
 }