Answer:
I have a gown but I'm not a priest; I have a crown but I'm not a king.
I help engines spin and pants stay up
You use a knife to slice my head but you weep beside me when I am dead
I am what no man ever yet did see, which never was, but always is to be. What am I?
You can read me both ways I wear; One way it's a number reversed a snare.
What has four fingers and one thumb, but is not alive?