diff --git a/lucene/core/src/java/org/apache/lucene/util/SloppyMath.java b/lucene/core/src/java/org/apache/lucene/util/SloppyMath.java
index d27c8b3677b..52a2087f283 100644
--- a/lucene/core/src/java/org/apache/lucene/util/SloppyMath.java
+++ b/lucene/core/src/java/org/apache/lucene/util/SloppyMath.java
@@ -33,7 +33,8 @@ package org.apache.lucene.util;
 public class SloppyMath {
   
   /**
-   * Returns the distance between two points in decimal degrees.
+   * Returns the distance in kilometers between two points
+   * specified in decimal degrees (latitude/longitude).
    * @param lat1 Latitude of the first point.
    * @param lon1 Longitude of the first point.
    * @param lat2 Latitude of the second point.