You know that loud wailing sound coming up the highway behind you? That's the siren on the police car racing along, lights flashing, chasing a speeder (not you, of course).
The word comes from the Sirens in ancient Greek mythology, the women whose beautiful singing lures sailors to wreck their ships on the rocks. Remember Odysseus, in The Odyssey of Homer? He had his crew plug their ears and then tie him to the mast, so that he could hear the Siren song but not be destroyed by it. Most women won't mind if you call them a siren — meaning they're dangerously beautiful. Who'd object to that?