noun
A somewhat formal or literary term for a necklace, often implying an ornamental or decorative piece worn around the neck. In everyday speech, ネックレス is more common.
彼女は真珠の頸飾を身につけていた。
She wore a pearl necklace.
その肖像画の貴婦人は豪華な頸飾をしている。
The noblewoman in the portrait is wearing a magnificent necklace.
Compound of 頸 (kei, 'neck') and 飾 (shoku, 'decoration'). The exact historical derivation is uncertain, but the word is formed from Sino-Japanese elements.