Why does "cooker" look like it's spelled wrong?

Did you ever do that.... spell a word and even though it's spelled right it still looks wrong??
Anyway, I received a beautiful pressure cooker as a gift and I'm deathly afraid to try it.... I have never used one before in my life ....All I can remember about them is the
exploding lid stories and I can't get past that.....Can someone give some tips on using one???
I was looking at the little booklet that comes with it and in
very tiny print it says, "
Read the directions carefully. Serious injury can occur."