noun
mesocarp; pith
Botanical term for the middle layer of a fruit's pericarp, between the exocarp (outer skin) and endocarp (inner layer). In citrus fruits, this is the white spongy part.
ミカンの中果皮は白くて苦い。
The mesocarp of a mandarin orange is white and bitter.
Endocarp: the innermost layer of the fruit, often hard or membranous.
Compound of 中 (middle) + 果皮 (fruit skin, pericarp). A straightforward botanical term.