also: じょうひ
The crust of the bread is crispy and delicious.
Please remove the film on the milk.
noun, noun which may take the genitive case particle 'no'
epithelium
Anatomical term for the tissue covering body surfaces and cavities. Usually read じょうひ, but うわかわ is also possible in medical contexts.
Epithelial cells cover the surface of the body.
Standard kanji spelling. When read うわかわ, it refers to outer layers, skin, bark, rind, etc. When read じょうひ, it is an anatomical term for epithelium.
Anatomical reading for epithelium. Not used for the general outer-layer sense.
Compound of 上 (うわ, 'upper') + 皮 (かわ, 'skin'). The reading じょうひ is the on'yomi version used in medical terminology.