noun
Anatomical/zoological term for the outer layer of skin or an animal's protective outer layer.
表皮の細胞は常に新しく生まれ変わっている。
The cells of the epidermis are constantly being renewed.
noun
Botanical term for the outer protective layer of a plant stem or root.
木の表皮を傷つけると、そこから樹液が出てくる。
If you damage the bark of a tree, sap will come out from there.
noun
facade; outer surface
Architectural term for the outer face or skin of a building; also used metaphorically for a superficial appearance.
このビルの表皮はガラスで覆われている。
The facade of this building is covered with glass.
表 (surface) + 皮 (skin). The word transparently means 'surface skin' and is used across scientific and technical fields.