Etymology of いい reading of 飯


I was surprised to learn that 飯 has the reading いい such as in 飯{いい}田{だ}橋{ばし},
and this is also [listed as an
"archaicism"](http://jisho.org/word/%E9%A3%AF-2) in my dictionary. I know this
kanji has the more usual kun-yomi めし (and on-yomi はん), but what is the
etymology of this alternate reading? In particular, is it originally a native
Japanese word (Yamato kotoba)?




Yes, い[ひ]{い} is indeed a yamato kotoba which can be found in
[万葉集](https://en.wikipedia.org/wiki/Man%27y%C5%8Dsh%C5%AB). From
[学研全訳古語辞典](http://kobun.weblio.jp/content/%E9%A3%AF):

> いひ 【飯】 名詞 飯（めし）。
>

>> 出典 万葉集 一四二 「家にあれば笥（け）に盛るいひを」 [訳] ⇒いへにあれば…。

いひ is even older than めし. めし gradually replaced いひ around the Muromachi
period, according to [this page](http://gogen-allguide.com/me/meshi.html).




Yes, い[ひ]{い} is indeed a yamato kotoba which can be found in
[万葉集](https://en.wikipedia.org/wiki/Man%27y%C5%8Dsh%C5%AB). From
[学研全訳古語辞典](http://kobun.weblio.jp/content/%E9%A3%AF):

> いひ 【飯】 名詞 飯（めし）。
>

>> 出典 万葉集 一四二 「家にあれば笥（け）に盛るいひを」 [訳] ⇒いへにあれば…。

いひ is even older than めし. めし gradually replaced いひ around the Muromachi
period, according to [this page](http://gogen-allguide.com/me/meshi.html).

