The caduceus (κηρύκειον), is the staff that Hermes wields in Greek mythology.
As a symbolic object it represents Hermes (and Mercury in Roman iconography) but also trade, negotiation and dealings with the gods.
The caduceus today is found everywhere depicting in the medical world, on ambulances, apothecaries and the likes which is in fact not correct: the traditional medical symbol; the rod of Asclepius, Greek god of medicine has only one snake and is never depicted with wings.
The meaning:
κηρύκειον kērukeion, meaning “herald's wand (or staff)" Latin meaning: herald or negotiator.
My attempt (took a few!) trying to pronounce the word:
https://dsound.audio/#/@gregan/caduceus
Despite my attempt trying to be serious I probably got that very wrong..
The symbol:
This is my contest entry. I always was fascinated by the iconography behind it.
Also thanks 
References