diff --git a/Terminology.md b/Terminology.md
index 7857e03..ea3ebfb 100644
--- a/Terminology.md
+++ b/Terminology.md
@@ -5,6 +5,8 @@ Official terminology of ReCodex which will be used in documentation and within c
 ## WebApp (ReCodex)
 Graphical frontend of the whole ReCodex. This part is used by teachers and students.
 
+* **Problem** - Teachers are creating problems which are solved by students. When problem is solved then students submit their solution, this solution with all other informations (needed by worker) is called submission. 
+
 ## QeueueManager (ZeroMQ)
 Handle incoming requests from php backend and forward them to actual workers, also handle answers from workers which has to be saved to the central database. (possibly files can be transfered through QM).