In wedding-dress terminology, the mermaid silhouette fits closely from the bodice to the knee before flaring toward the hem.
The shape is named for its resemblance to a mermaid’s tail. Its fitted upper section emphasizes the torso and hips, while the skirt expands below the knee, creating a dramatic outline. The flare may be formed with layered fabric, pleats, godets, or a structured underskirt.
Mermaid dresses are often confused with trumpet silhouettes. A trumpet gown also has a close-fitting upper section, but it generally begins flaring higher on the thigh, producing a less sharply tapered shape. A fit-and-flare dress is a broader term that can describe either style.
Unlike an A-line dress, which widens gradually from the waist or hips, a mermaid gown keeps a narrow line for longer before opening out. The design can restrict walking compared with fuller silhouettes, so many versions include a slit, back godets, or a separate reception skirt.