I don't know if a pretonic sounds more like a drink intended to take the edge off your thirst before you start on the gin, or some medicine to keep you in good condition.
It's certainly a more inviting name than vitamin tablet.
Rather sadly, a pretonic is neither of those pleasant and useful things, but a term to describe the bit of a word immediately before the syllable that's most heavily stressed.
The pretonic of the word pretonic is therefore pre, in the word conditioning con, and in the word abracadabra it's ca.
On the other hand, the words pleasant and useful, having their stress on the first syllable, don't have a pretonic at all.
But I really don't think they're bothered.
Word To Use Today: one with a pretonic, perhaps. Pre- comes from the Latin word prae, before, and tonic is from the Greek tonos, which means tone.