Can anyone tell me what this detail is called on a dress?

If I'm understanding your description correctly, the first looks like a true mermaid (tight to the knee then flares) while the second is a fit and flare (starts to flare around your thigh). Is that what you're referring to?

View Quoted Comment I’m not sure that’s what it is. Here is two more pictures. Both of the gowns below are described as “fit and flare” but the amount of maybe “ruffles”? (The way the dress gathers around the knee) is different. Some dresses just have a smooth finish and some are more wavy in how they gather.

I think it’s just the difference between having a petticoat underneath or not. Wearing one puffs the bottom out a bit and creates a straighter bottom without the folds

One is fit and flare, the other is trumpet or mermaid

Top a trumpet, bottom a fishtail
1.How it is done, by sliwly adding material going down or gathering in one spot, and 2. Where it is gathered. ....1. In order to have a bottom looser or wider at the hem than the hips, of one piece: When cutting the fabric pieces neckline to hem,the center front piece, the side front pieces are cut wider with just a little more material, at bust, narrower waist, wider hip, then gradually larger. that leaves usually 4-6 seam pieced places where you can add fabric, so it is increased in width or decreased gradually, same on back. Pieces go top neck to waist, then waist to hem, or neckline to hem in one solid piece. The other way is to piece the upper body, then cut a long strip and gather it like a skirt, and attach it to the lower leg. The third way not shown here is when you have slits lower down on the dress, and add triangular pieces in pleats, gussets. 2. fit and flare styles, body hugging tops with skirts flaring bigger going down, can be gathered at different places. They may have a slim top to 3-6 inches below the regular waist, then flair, drop waisted. They may hug the body to mid thigh to knee then flare, Trumpet bell skirts. They may flare at the knee, still called a trumpet if in one piece coming down as it goes from narrow to wider, gently. Or a fishtail if widens at the knees due to attaching gathered material, or adding triangular gussets. Or a mermaid if the flaring starts well below the knee at the calf.

How it is put together:






Cut as one piece, sheath a little bigger at bottom, trumpet skirt in one piece, skirt with lower part of gathered or pleated with gussets, then what each piece that makes up a gentle bell front with a train or puddled back, 2-4 make the skirt part, sewed to a body hugging top.

View Quoted Comment I can see how that would probably affect it as well.

View Quoted Comment Thank you for such a thorough response! I had to read it a couple times because it’s very technical but I feel like I really learned! This makes sense. I think some of the people that have helped me try on dresses may not know the difference between fit and flare/mermaid/trumpet or different designers label the looks a little differently.

View Quoted Comment Most know that trumpets flaring high mid thigh are flattering to a curvy woman who still has a waist, and that mid calf sudden sharp flare is horrid on such people. But people mix fishtails, spread close to knee, with mermaids that flare calf or lower, especially. You noticed those with sewn on bottoms or tails, versus those in long pieces vertically. Structure. Now each you try, see what flatters according to where it flares, mid hip/ or drop waisted, or mid thigh toward knee, or knee, or calf. You will begin to find one suits your proportions best.

View Quoted Comment Absolutely. I think I’ll have a better eye now when trying on dresses. It was a detail I couldn’t explain. Now that I see it I can notice the pattern and as you said, figure out what I think is flattering.