Weight is the thickness attribute of the outline of a shape, picture, or any other such slide element. You can change the weight all the way from a hairline thin line to a chunky thick line. To learn more about how to edit the weight, choose one of the following links depending upon your PowerPoint version:
Formatting Outlines for Shapes in PowerPoint 2013 for Windows — Weight
Formatting Outlines for Shapes in PowerPoint 2010 for Windows — Weight for Windows
Formatting Outlines in PowerPoint 2007 for Windows — Weight and Dash
Formatting Lines (Outlines) for AutoShapes in PowerPoint 2002 and 2003 for Windows
Microsoft and the Office logo are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries.