Hi Loren :) Halter (clothing) is a piece of women's clothing that is held in position by a strap that goes behind the neck so that the upper back and shoulders are not covered. the phrase Orchid-colored can be reworded as 'having Orchid color' as in a bright rich purple.

Hi Loren 'orchid-colored' means that the dress has probably a purple color, it refers to the orchid plant. 'halter dress' is a dress that is tied behind the neck. So the phrase means 'a purple dress that is tied behind the neck'. Kind regards Karen