noun
old woman's gray hair
Formal or literary term for the gray hair of an elderly woman. Not used in everyday conversation.
九十九髪の老女が静かに語り始めた。
The old woman with gray hair began to speak quietly.
白髪 is the common word for gray or white hair, used for anyone. 九十九髪 is a literary term specifically for an old woman's gray hair.
The reading つくもがみ is associated with the kanji 九十九 (ninety-nine), suggesting advanced age. The exact derivation is uncertain, but the term is a poetic expression for the hair of a very old woman.