(I'm not sure this is the right place to write/ask, but i'll do it).

In today's word, "canonical", the etymology says

Quote:
ETYMOLOGY:
From Latin canon (measuring rod, rule), from Greek kanon (rule).


I am trying to understand the link between the Latin and Greek and the more modern "canon" (or cannon as it seems to be spelled in English) which is a piece of artillery.

"Obvious" reasoning would suggest that the first cannons were measured with a measuring rod (?) but that's just a hypothesis.

Does anyone know how the word (and spelling evolved to this ?

thanks
Serge