凸

JŌYŌ KANJI · Secondary school

convex

convex · beetle brow · uneven

5 strokesRadical 17U+51F8
01

Readings

Official Jōyō readings in table order

On’yomi 音読み

トツ

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

でこ

These are outside the official Jōyō list above. A listed reading is not necessarily common in modern use.

02

Origin and meaning

An object raised high at its center.

Earlier sense recorded in the sourcecentral protrusion; pictograph
Meanings in the learning dataset todayconvex · beetle brow · uneven

Read the source entry ↗

03

Written form

No parenthesized form is given in the official Jōyō index for this character.

Dictionary radical凵うけばこ · open box
Stroke count5May vary for alternate forms.
UnicodeU+51F8Modern character encoding, not an origin date.

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.

04

Examples in the official table

  • 凸版,凸レンズ,凹凸

Official notes

  • 凸凹(でこぼこ)
05

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 凸.

凸 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 凸 has not been verified in the sources attached to this entry.

Agency for Cultural Affairs: writing history ↗ · 2010 Jōyō notice ↗

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