"to fission (fissile being an adjectival form), from Latin 'to split'."

Does this mean "Missile" means "to miss"? 'Cause boy have we been using those things wrong :-)

No, 'missile' means 'something that is sent' or 'suitable for throwing'

The missile needs to know how to miss, because it knows where it is from knowing where it isn’t.

https://youtu.be/bZe5J8SVCYQ