The following are the Building Blocks (or) Key components of Power BI
Visualization is a visual representation of data.
Example: Pie Chart, Line Graph, Side by Side Bar Charts, Graphical Presentation of the source data on top of geographical map, tree map etc.
Dataset is a collection of data that Power BI uses to create its visualizations.
Example: Excel sheets, oracle or sql server tables.
Report is a collection of visualizations that appear together on one or more pages.
Example: Sales by Country, State, City Report, Logistic Performance Report, Profit by Products report etc.
Dashboard is single layer presentation of multiple visualization. i.e we can integrate one or more visualizations in to one page layer.
Example: Sales dashboard can have pie charts, geographical maps and bar charts.
Tile is a single visualization in a report or on a dashboard.
Example: Pie Chart in Dashboard or Report.