射干玉

From Old Japanese.

The 射干 part, read yakan in Sino-Japanese, refers to the 檜扇 (hiōgi, “blackberry lily, Iris domestica”).

• (Tokyo) ぬばたま [nùbátámá] (Heiban – [0])^[1]
• IPA^(key): [nɯ̟ba̠ta̠ma̠]

射干(ぬば)玉(たま) • (nubatama) 

1. a blackberry lily seed or fruit, usually one that is jet-black and spherical

• 射干(ぬば)玉(たま)の (nubatama no, pillow word)

Appears to be a Heian-period shift of Old Japanese 射干玉 (nubatama) or classical 烏羽玉 (ubatama).

射干(むば)玉(たま) • (mubatama) 

1. (archaic) a blackberry lily seed or fruit, usually one that is jet-black and spherical

• 射干(むば)玉(たま)の (mubatama no, pillow word)
• 烏(う)羽(ば)玉(たま) (ubatama)

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “Where did the initial nuba- come from?”)

射干玉 (nubatama) (kana ぬばたま)

1. a blackberry lily seed or fruit, usually one that is jet-black and spherical

• 射干玉の (nubatama no₂, pillow word)

• Japanese: 射干玉 (nubatama, mubatama), 烏羽玉 (ubatama)