What is a magic word? Could it be: A word which is not just a symbol: a word with causal power without mediation through a mind or body.
Such spells exist. Just say "noise" to yourself, and lo it appears. Shout "Police!" long enough and you will indeed summon the demon you name. "Confusion!", in company, likewise but quicker. "Speech-act". "Disquotation" après-moi. "Entropy!" arguably.
(This is all quite aside from computer code, those living causal words that are eating more and more of the economy and of the intellect, and so of the world.)