This is a dress that is tightly-fitting to the body until it reaches below the hips and starts to flare. The flare starts at mid-thigh.
That is between the knee and the hips. The dress begins to gradually come away from the body. The open skirt begins to take shape of a trumpet hence the name.
The trumpet dress has always been the best choice for designers specially in designing bridal wear and evening gowns.
Traditionally the trumpet was tight over the hips and flared like a trumpet down to the hem.
A trumpet dress is similar to the mermaid gown. The flare is much more gradual than that of the dramatically flared mermaid dress.
The dress adds feminine curve to a straight figure. The dress allows more freedom of movement compared to the mermaid. The dress can fit different body shapes.