Pleach - 1. To interweave branches or vines for a hedge or arbor. 2. To make or renew (a hedge, arbor, etc.) by such interweaving. 3. To braid (hair).
The Christmas Narcissa turned seven, her mother braided her hair in a very complicated manner. Seven French braids curved round the crown of her head, only to be gathered together by one large tortoiseshell clasp. Beneath the clasp, Cissy's curls tumbled loose down her back.
Cygnus, Druella, Bellatrix, Andromeda. Orion, Walburga and Sirius. Seven Blacks; seven people worthy of Narcissa's affection. Seven braids. A braid for each person.
The symbolism wasn't empty. Oh no. Druella knew what she was doing. In weaving Narcissa's hair into that style, she was daring anyone to contradict her when she called Narcissa a Black.