JŌYŌ KANJI · Secondary school
concave
concave · hollow · sunken
Readings
Official Jōyō readings in table order
On’yomi 音読み
Kun’yomi 訓読み
None listed in this source.
Additional readings in the learning dataset
On’yomi
None listed in this source.
Kun’yomi
These are outside the official Jōyō list above. A listed reading is not necessarily common in modern use.
Origin and meaning
A pictograph directly traces a surface dipping inward.
Written form
No parenthesized form is given in the official Jōyō index for this character.
Compare manuscript and printed examples in the HNG historical glyph archive ↗. Where available, its dated samples document written forms; they do not establish the first use of this character in Japan.
Examples in the official table
- 凹凸，凹面鏡，凹レンズ
Official notes
- 凸凹（でこぼこ）
When did it enter Japanese?
Chinese characters reached Japan through a long process of contact. Early inscribed objects and sixth-century Japanese names are documented; this is context for the writing system, not a first date for 凹.
凹 appears in the current Jōyō kanji table published on 30 November 2010. This records modern standard status, not the date the character was first used in Japan.
A dated first Japanese use for 凹 has not been verified in the sources attached to this entry.
Agency for Cultural Affairs: writing history ↗ · 2010 Jōyō notice ↗