The types of pruning and some terminology.
There are many different types of pruning that can be done to your trees and much of it has to do with the crown (the area where branches grow from the trunk) :
Crown Thinning- this method increases light and air flow. It also reduces the weight from the heavier branches.
Crown Raising/ Elevation- doing this provides clearance for buildings, signs, vehicles, and enhances your view.
Crown Reduction- a reduction reduces the tree height, spread, and the weight of the crown.
Crown Cleaning- the selective removal of deadwood, diseased wood, broken, or weakly attached limbs.
Crown Restoration- improves the tree structure, form, appearance. This type of pruning is usually done on storm-damaged trees.
Utility Pruning- this type of work is usually done by...you guessed it...utility companies. This is typically done to keep trees and their branches from breaking during storms so that they don't take out your electricity or cable.
Vista Pruning- selective pruning that allows for a specific view.