It is Microsoft cloud based Business intelligence Tool. It works with Excel and Office365 to analyze and visualize the data.
Power Query : Enables users to easily search and access their organization data within Excel. It works like a data explorer. Transform the raw data into a tabular form dataset that can be used with Excel or Power Pivot.
Power Map : The Power Map is used for creating 3D data visualization tool for mapping, exploring and interacting with geographic data.
Power Pivot : For creating and customizing flexible data models within Excel. It’s the engine that runs all the calculations, hosts all your data and creates the analytical model
Power View : For creating interactive charts, graphs and other visual representations of data.
It can be grouped under three major category
1.The BI add-on for Excel
2.The actual cloud service or BI Site (SharePoint Online)
3.The new REST API (for development) This is the latest addition to the family. The ability to interact with Power BI using a REST API in order to create some custom applications. You can create your own connectors or even create applications that will interact with a dataset in order to add new rows or alter such dataset