ivory palm
A tropical palm species (Phytelephas macrocarpa) whose hard white seeds resemble ivory.
The seeds of the ivory palm are sometimes used as a substitute for ivory.
Katakana spelling is common for this plant name; usually written in kana.
Kanji spelling is rare and mainly used in botanical contexts.
From 象牙 (ぞうげ, 'ivory') + 椰子 (やし, 'palm'), referring to the ivory-like seeds.