Microsoft Fabric uses a data lakehouse architecture, which means it does not use a relational data warehouse (with its relational engine and relational storage) and instead uses only a data lake to store data. Data is stored in Delta lake format so that the data lake acquires relational data warehouse-like features (check out my book that goes into much detail on this, or my video). Here is what a typical architecture looks like when using Fabric (click here for the .vsd):
Click through for the image as well as James’s explanation of the components.