Update index.md

Author: badmonster0

docs/docs/sources/index.md

@@ -8,13 +8,13 @@ description: CocoIndex Built-in Sources
 
 In CocoIndex, a source is the data origin you import from (e.g., files, databases, APIs) that feeds into an indexing flow for transformation and retrieval.
 
-| Source Type    | See Also                    |
-|------------------|-------------------------|
-| LocalFile | [Local File System](/docs/sources#localfile)   |
-| AmazonS3 | [Amazon S3](/docs/sources#amazons3)   |
-| AzureBlob | [Azure Blob Storage](/docs/sources#azureblob)   |
-| GoogleDrive | [Google Drive](/docs/sources#googledrive)   |
-| Postgres | [PostgreSQL](/docs/sources#postgres)   |
+| Source Type    | Description                        |
+|----------------|------------------------------------|
+| [LocalFile](/docs/sources#localfile)     | Local file system                        |
+| [AmazonS3](/docs/sources#amazons3)       | Object store (Amazon S3 bucket)          |
+| [AzureBlob](/docs/sources#azureblob)     | Object store (Azure Blob Storage)        |
+| [GoogleDrive](/docs/sources#googledrive) | Cloud file system (Google Drive)         |
+| [Postgres](/docs/sources#postgres)       | Relational database (Postgres)           |
 
 Related:
 - [Life cycle of a indexing flow](/docs/core/basics#life-cycle-of-an-indexing-flow)