Before I Say Good-Byeを読んでいます。
She showered and dressed, putting on white chinos, a short-sleeve blouse, a lightweight blue denim jacket and sandals.
It’s almost time for a cut, she decided as she brushed her hair into a French twist. Then she paused suddenly, as something in the mirror struck her as odd. It was the face--the face she saw there seemed almost to be that of a stranger, the expression strained and anxious. This ordeal has definitely taken its toll, she realized. Something had better be resolved soon, or I will be a total wreck.
"French twist" がどんな髪型か気になりました。
・Oxford English Dictionary: A woman's hairstyle in which the hair is tucked into a vertical roll down the back of the head.: I nodded at my older sister, her long brown hair in a neat French twist, no loose strands to be seen.
だいたい分かった気がしますが、こういうのは写真が一番。インターネット検索で幾らでも写真が見つかりました。例: https://jp.pinterest.com/chrisnair/french-twist-hair-tutorials/
私は "French twist" を知りませんでしたが、女性には常識かな。