Answer:
Defends your noggin from the hard pavement
Major or minor I can be, when you touch me make sure you that you’re on the right key.
The distance from the top of your head to the floor standing up straight.
With sharp edged wit and pointed poise. It can settle disputes without making a noise.
Lots of them make up a word, And lots of words are in them. It's easy when you think about it. A while ago we stamped and mailed them.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?