diff --git a/Concepts.md b/Concepts.md
index cb61863..e097c74 100644
--- a/Concepts.md
+++ b/Concepts.md
@@ -39,6 +39,13 @@ Categories are hierarchical structures meaning that you can create logical trees
     * Capacitors
     * Resitors
 
+### Supplier
+A Supplier is a vendor / distributor where you can buy/order parts. Price informations of parts are associated with a supplier. 
+
+### Manufacturer
+A manufacturer represents the company that manufacturer / build various parts (not necessary sell them). If the manufacturer also sell the parts, you have to create a supplier for that.
+
+
 
 ## Attachments
 ### Attachment