sheath dress       
noun [ C ] uk/ˈʃiːθ ˌdres/ us/ˈʃiːθ ˌdres/
 (包臀)修身连衣裙
a simple dress that is fairly straight but fitted around the waist and hips 
  She wore a lavender-lilac sheath dress topped with a coat of the same colour. 她穿了一条淡紫丁香色的修身连衣裙,外面配了一件同样颜色的外套。 
 At the adjacent table sits Diane in a sheath dress of white and silver. 黛安坐在邻桌,身穿白色配银色的修身连衣裙。 
 - More examples
 - She sat down beside him in her shimmering Versace sheath dress.
 - She's wearing a fabulous black silk sheath dress and satin shoes.
 - The collection featured grey check trouser suits, silver cashmere pencil suits and embroidered black lace sheath dresses.