A Pivot Point is the point or position where an object is anchored in the 3D space i.e. on the scene. In other words, it is the precise location of your object(s) on the scene.

• A Pivot Point or Pivot Points (depending on how many objects are on the scene) also controls how your object(s) rotate and scale on the scene.
• Changing the Pivot Point of an object allows you to change the rotation point on the object.

This article will address the following questions:

1. How do you change the Pivot Point of an object?
2. How do you manipulate an object from the Pivot Point? 

How do you change the Pivot Point of an object ?

• You can change the Pivot point of an object in object properties. This is applicable only to nodes that contain 3D data (It is not possible for empty objects and lights.) Learn more: FAQ: Why can't I see Pivot in Object Properties.

• Using the "Set Pivot", you can set the position of the pivot relative to the bounding box of a selected object. (For example, this means the bottom will align to the bottom of the bounding box.)

• You can also manually change the pivot location by offsetting it from its original position (For example: Value 1 in the x value will offset the pivot 1 unit value (e.g. meter) in the x-direction, relative to where the pivot originally was.)

How do you manipulate the Pivot Point of an object ?

More information here.