1.
endothelium; inner skin (anatomy)
In anatomy and medicine, the thin layer of cells lining the inside of blood vessels, the heart, and other hollow organs. Contrasted with 外皮 (outer skin) and 中皮 (mesothelium).
2.
inner rind; inner skin (of fruit, seeds, etc.)
In botany and cooking, the thin white or translucent membrane found just inside the outer peel of citrus fruits, chestnuts, and similar foods. Often removed for a better texture or flavor.
Composed of 内 (inner) and 皮 (skin). A technical compound with parallel counterparts in 外皮 (outer skin), 中皮 (mesothelium), and 表皮 (epidermis).
Usage
The anatomical sense (sense 1) is the most common in writing — it appears in medical journals, health articles, and biology textbooks, often in combinations like 血管内皮 (vascular endothelium) or 内皮細胞 (endothelial cells). The culinary/botanical sense (sense 2) appears in cooking instructions and describes the thin inner membrane that must be removed from chestnuts, citrus fruits, and similar foods. Context makes clear which sense is intended.
Common collocations
- 血管内皮: vascular endothelium
- 内皮細胞: endothelial cells
- 内皮機能: endothelial function
- 内皮を剥く: to peel off the inner skin (of a fruit)
- 栗の内皮: the inner skin of a chestnut