diff --git a/Volume-Server-API.md b/Volume-Server-API.md
index de4acd5..ee9ae05 100644
--- a/Volume-Server-API.md
+++ b/Volume-Server-API.md
@@ -4,14 +4,14 @@ You can append to any HTTP API with &pretty=y to see a formatted json output.
 
 GET/HEAD operations are direction http requests to file ids, e.g., `http://127.0.0.1:8080/3,01637037d6`.
 
-| Parameter | Description | Default |
+| URL Parameter | Description | Default |
 | ---- | -- | -- |
 | readDeleted | if "true", possibly read a deleted file. Does not work if volume server is restarted or the volume is compacted. | false |
 | width  | if the stored file has ".png", ".jpg", ".jpeg", ".gif", apply resizing | empty |
 | height | if the stored file has ".png", ".jpg", ".jpeg", ".gif", apply resizing | empty |
 | mode   | if resizing, "fit", or "fill". Or just resizing, unless width==height, which default to thumbnail mode | empty |
 
-| Header | Description | Default |
+| Request Header | Description | Default |
 | ---- | -- | -- |
 | Authorization | Json Web Token for reads issued by master | empty |
 | Range | for http range request, support multiple ranges | empty |
@@ -39,7 +39,7 @@ The size returned is the size stored on SeaweedFS, sometimes the file is automat
 | ts | modification timestamp in epoch seconds | empty |
 | cm | content is a chunk manifest file | empty |
 
-| Header | Description | Default |
+| Request Header | Description | Default |
 | ---- | -- | -- |
 | Content-Encoding: gzip|the uploaded content is already compressed to gzip | empty |
 | Content-Encoding: zstd|the uploaded content is already compressed to zstd | empty |