Ok so right out of the destination wedding bible it says...
Black Tie Optional - This is if your wedding is formal
Formal Dress - dressy but not black tie
Cocktail Attire - he wears a suit or sport coat she wears a cocktail dress
Beach Formal - for an elegant beach wedding; it implies colorful semiformal dresses and summer suits
Beach Chic - sundresses & slacks and polos
Island Festive or Festive Attire - sundresses & island shirts slacks to shorts
Jacket Required - can be added to of the less formal dress codes if you would like men to not wear shorts and add a jacket
[*]Flip Flops Required, Beach Casual, Sarong Style or Tropical Attire - flip flops paired with in-fomal but wedding appropriate wear like sundresses and khakis with white linen shirts. but be forewarned guess my end up in tshirts and shorts
Now, I didn't know what half of these meant without the definition next to it so you can say the phrase on the invite and what it means to you or if you have a wedding website put the definition on there or if you are sending out a newsletter it can go there as well.
Hop ethis helps