What is the 「ひ」 in 「ひづめ」（蹄）？


The word 蹄 (ひづめ) means _hoof_ in Japanese. Since the meaning is similar to つめ
( _claw_ ), and since it's spelled specifically with づ, it seems like this
word is made up of two parts:

> ひ ＋ つめ

I can't figure out what the ひ part might mean, though. It would make sense if
it meant a large four-legged animal, or if it meant horse or something else
along those lines. But I can't find any information about it in dictionaries
or by searching on Google. (Has the origin of ひ in this word been lost?)

I also looked through lists of kanji by _on_ and _kun_ readings looking for
reasonable candidates for ひ, but I wasn't able to find anything that seemed
appropriate.

Is it possible it comes from a shortening of 扁爪 (ひらづめ)？




According to [Yamaguchi Masumi (2007)](http://books.google.ca/books?id=TfU_-
jVc15sC&pg=PA395) (I'm using a hard-copy), the ひ（ = 脚・四肢・足） originally
referred to the limbs/feet/legs of horses and sheep. It was then combined with
つめ to form ひづめ, and then extended to mean the hooves of any mammalian
quadruped.

It should be noted, however, that all this was original research done by
Yamaguchi, who apparently is not a historical linguist (so far as I can tell).
So although I'm happy to accept Yamaguchi's explanation, he doesn't cite any
sources, which makes me a little skeptical.

But going through UVirginia's online library, I've found evidence of 爪（つま・つめ）
being used to mean "hoof" as late as ~1360AD. Phrases like
「馬の爪」、「鹿の爪」、「駒の爪」、and 「爪音」 are also attested prior to 1360, suggesting that
the word ひつめ/ひづめ must have appeared around or after this time as a combination
originating from つめ（爪）.

In conclusion, [蹄]{ひづめ} is (almost) definitely a concatenation of ひ-, which
_may_ mean "ungulate limb", and -つめ 'claw/hoof'; and probably emerged in the
13th or 14th centuries.

* * *

Some other facts you might find interesting:

  * Yamaguchi claims that the ひ in [膝]{ひざ} and [肘]{ひじ} also share this root with ひづめ, making them reflexes of the same cognate.
  * The word ひづめ（蹄） was conspicuously absent in all the other Japanese etymology dictionaries/books I looked through in my university's East Asian library.




According to [Yamaguchi Masumi (2007)](http://books.google.ca/books?id=TfU_-
jVc15sC&pg=PA395) (I'm using a hard-copy), the ひ（ = 脚・四肢・足） originally
referred to the limbs/feet/legs of horses and sheep. It was then combined with
つめ to form ひづめ, and then extended to mean the hooves of any mammalian
quadruped.

It should be noted, however, that all this was original research done by
Yamaguchi, who apparently is not a historical linguist (so far as I can tell).
So although I'm happy to accept Yamaguchi's explanation, he doesn't cite any
sources, which makes me a little skeptical.

But going through UVirginia's online library, I've found evidence of 爪（つま・つめ）
being used to mean "hoof" as late as ~1360AD. Phrases like
「馬の爪」、「鹿の爪」、「駒の爪」、and 「爪音」 are also attested prior to 1360, suggesting that
the word ひつめ/ひづめ must have appeared around or after this time as a combination
originating from つめ（爪）.

In conclusion, [蹄]{ひづめ} is (almost) definitely a concatenation of ひ-, which
_may_ mean "ungulate limb", and -つめ 'claw/hoof'; and probably emerged in the
13th or 14th centuries.

* * *

Some other facts you might find interesting:

  * Yamaguchi claims that the ひ in [膝]{ひざ} and [肘]{ひじ} also share this root with ひづめ, making them reflexes of the same cognate.
  * The word ひづめ（蹄） was conspicuously absent in all the other Japanese etymology dictionaries/books I looked through in my university's East Asian library.

