To Black Tie, or Not to Black Tie

So I have a black tie event coming up, and everyone is asking what they should wear since the event is "black tie" and those words seem to throw some people off. I have always assumed that black tie was a fancy, floor length dress. But in this day and age, black tie has taken on a whole new meaning. So obviously in my confusion, I took to the google. Emily Post's Etiquette defines black tie as a "formal evening dress or short, dressy cocktail dress." So now I'm thinking I also have the option of a shorter, fancy cocktail dress. But if you go for the cocktail dress, personally, make sure its a fancy material/decorations, i.e. silk, beaded, etc. And of course, bring out the jewels. Black tie events make for a prime opportunity to wear those huge, sparkly dangle earrings. So now after my research, Im thinking I have a lot more options for this event. And I hope I cleared it up for others as well.