When you are looking for a particular style of dress, it can be difficult if you don't know the names of the silhouette that you are looking for. There are a few common silhouette names that you should know that will make it easier for you to find exactly what you are looking for through vendors like Shanalina.
An empire dress has a fitted bodice that ends under the bust line. There is often some kind of detail that delineates the end of the bodice, something like a ribbon, lace, or some other decoration. The fact that the separation between bodice and skirt starts under the bustline makes it look like the wearer has a very high waistline. The skirt can be any length from mini to maxi, but you often see empire dresses as maxi dresses. The skirt is less fitted than the bodice, but is generally not completely loose. The style comes from early 1800s France and the Napoleonic Empire. Jane Austin would be very familiar with an empire style dress.
Tunic dresses generally end a few inches above the knee. Tunic dresses are relatively straight without any real definition to them. They are also a little looser so that they aren't exactly fitted, but not so loose as to be something like a trapeze or A-style dress. The tunic dresses can be anything from sleeveless to long sleeved. A shorter tunic style dress may be worn over leggings. If you are looking for some definition around the waist when you are wearing a tunic dress, then you may want to consider wearing a belt of some kind at your waistline.
A trapeze dress can also be called an A line dress. Basically, these dresses are shaped like a capital A. They are narrow at the shoulder and widen out at the dress gets longer. They generally aren't much longer than the knee because the dresses may start to involve too much material and flare below the knee. This style is pretty versatile. It can work for people of just about any body shape and can be very comfortable for a woman who is looking for a maternity dress since there aren't any places where the dress may bind uncomfortably.
Trying to find the right dress when you aren't sure of the style names can make things more difficult. Knowing a few names of different common silhouettes can help you.