First opened Friday, January 13, 2006
貝
かい
- head-high (atamadaka): falls after mora 1
How to read it: a line over a kana means the voice is high there, and ↓ marks where it drops. A kana with no line is low. With no ↓ the pitch stays high to the end and does not drop even on a following particle (が, は).
shell, shellfish
Kai, “shell”, was kapi in Old Japanese, from Proto-Japonic *kapi.
Taken apart
No breakdown is shown for this word: Wiktionary's text for it doesn't give a split that spells the word and joins to its reading, and any other split would be a guess.
Written with 貝
In a sentence
貝は好きではない。
I don't like shellfish.
火力とお鍋と貝の種類によるわ。
It depends on the strength of the flame, the pan used and the type of ingredients.
Sentences are from Tatoeba (CC BY 2.0 FR), picked by fixed rules from a dated export and shown unchanged. Nobody has reviewed them one by one.
What Wiktionary says
Quoted line by line from Wiktionary's Etymology section for this reading, taken from one dated dump so it can't change underneath us. Nothing below is paraphrased.
- “⟨kapi₁⟩ → */kapʲi/ → /kaɸi/ → /kawi/ → /kai/”
- “From Old Japanese, from Proto-Japonic *kapi. Appears voiced in the Kojiki of 712 CE in a compound, with the phonetic man'yōgana spelling 賀比, and in the Man'yōshū, completed some time after 759 CE.”
Source: Wiktionary: 貝 (dump of 2026-09-02), available under CC BY-SA 4.0. Reading, meaning and part of speech from JMdict, and kanji readings from KANJIDIC2 (EDRDG).
Other readings of 貝 on the same Wiktionary page
These describe other words written the same way, not かい. They are quoted for context: the parts, layer and processes of this word are not taken from them.
ばい
- “Probably ultimately from Middle Chinese 貝 (MC pajH). Compare modern Min Nan pronunciation buê⁶, Cantonese bui³, Mandarin bèi.”
- “First attested in 1284.”
What the labels mean
- 和語 Native Japanese
- Words that were already Japanese before Chinese vocabulary arrived — usually written with kun'yomi and often short.
- Compound
- Two or more words or stems joined into one.
- Sound change
- The pronunciation shifted over the centuries.