concave roof tile
In traditional Japanese roofing, the concave tile that is laid with the hollow side up to channel water; paired with the convex 牡瓦 (おがわら).
On the roofs of traditional Japanese buildings, concave tiles and convex tiles are laid alternately.
Standard kanji spelling using 牝 (female) to indicate the concave tile that receives the convex 牡瓦 (male tile).
Variant spelling using 女 (woman) instead of 牝; less common but still encountered.
Compound of 牝 (め, 'female') and 瓦 (かわら, 'tile'), referring to the concave shape that receives the convex 'male' tile.