You can navigate directly to the page by clicking here!
If you are in Brightmetrics and looking for the meanings behind some of the dimensions or values that Brightmetrics reports upon, the easiest way to find the data definitions page is to select the Help option from the Sidebar menu and then select Data Definitions Page from the bottom of the Help Options dialog box.
Once you are on the Data Source Definitions Page, you can search for the field you would like more information on.
Also, we've tried to make it easier to see the definitions of the Values and Dimensions of data within Brightmetrics by allowing you to hover your mouse over the terms when you've selected Edit Mode in On Demand Reports which reveals a pop-up box with definition and Use Tips that persists on screen while your cursor is over the Value or Dimension:
Again, you can also just go straight from here to http://brightmetrics.com/support/datadefinitions/