Peace que a blusa na foto não coincide com a descrição do decote. Veja explicação e fotos neste artigo da Wikipédia. Em seguida, compare com a descrição em português:

“A cowl neck is a neckline consisting of loose draped fabric around the collarbone.[1] The term can describe the neckline of a wide variety of garments, from the draped neckline of an evening gown to a raised neckline of knitwear similar to a turtleneck.[2] The neckline was introduced in the 1920s by Madeleine Vionnet based on her study of ancient Grecian sculptures.[3] The style is named for the cowl, a feature of monastic dress that serves as both a collar and a hood.

Inspired by the draped garments of antiquity, Madeleine Vionnet created the cowl neckline in the 1920s using the bias cut technique that she helped to popularize.[3] The cowl neck enjoyed the peak of its popularity in the 1930s.” https://en.wikipedia.org/wiki/Cowl_neck

Photo of cowl-necked garment created by Denise Vanderveld-Borgeaud (c. 1930):
https://commons.wikimedia.org/wiki/File:Huispyjama_met_wijde...

Photo of Kate Middleton’s in her cowl-necked bridesmaid gown: https://commons.wikimedia.org/wiki/File:Pippa_Middleton_Prin...

cowl: capuz
https://en.bab.la/dictionary/english-portuguese/cowl

draped: drapeado; e.g. draped sleeve: manga godê, manga drapeada
https://en.bab.la/dictionary/english-portuguese/draped

Example Sentence

“Geralmente, o material furtivo é um não-não para bustos maiores, mas o decote com capuz drapeado torna este vestido no estilo dos anos 20 mais um item obrigatório.” https://ao.eveningontheriviera.com/7254-how-to-find-the-perf...

Foto: vestido de noiva por Savannah Miller
https://eveningontheriviera.com/img/how-to-find-perfect-wedd...

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Note added at 11 hrs (2021-07-11 11:56:01 GMT)
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Correção: Photo of Kate Middleton in her cowl-necked bridesmaid gown