Update docs/source/design/concepts/index.rst

Co-authored-by: Natasha Singh <[email protected]>

docs/source/design/concepts/index.rst

@@ -4,7 +4,7 @@
 Concept Schema
 ==============
 
-A key part of the ingest library is the intermediate model of the
+A key part of the ingest library is the intermediate model that raw data is mapped to. The intermediate model is called the "concept schema". The concept schema is essentially just a list of column names that follow a standard that denotes the type/concept and the attribute (e.g. `PARTICIPANT.GENDER`). Data that has been mapped to the concept schema is later transformed into the final schema that is used to create the tables in the target API.
 "concept schema". This concept schema is a representation of the data that is
 being ingested, and is used to generate the final schema that is used to create
 the tables in the target api.