noun
diamond-shaped mochi
A traditional layered mochi in pink, white, and green, cut into a rhombus shape and associated with the Doll's Festival (Hinamatsuri).
ひな祭りには菱餅を飾ります。
We display diamond-shaped mochi for the Doll's Festival.
From 菱 (water caltrop, rhombus) + 餅 (mochi). The shape is said to resemble the leaf of the water caltrop.