Origin of the word 烏有


I saw the phrase 烏有{うゆう}に帰{き}す, which means to "become nothing" as if turning
to ashes. The word "烏有" means nothing, but its parts are 烏 (crow) and 有 (to
be). How did 烏有 come to mean nothing?

When I consulted a dictionary
([kotobank.jp](https://kotobank.jp/word/%E7%83%8F%E6%9C%89-441691)), it said
it means: 「烏(いずく)んぞ有らんや」. What does that mean? I'm not sure how to translate
that. Also, is there a place where the word is first used?




## 烏有 as _on'yomi_ : _uyū_

As others have noted in the question comments, 烏有 read as _uyū_ derives from
Classical Chinese. Its origins there appear to be based on 烏 (not " _crow_ "
here, instead used phonetically in Middle Chinese as an interrogative and
negative indefinite pronoun, as noted by snailboat and Derpius in the comments
above) + 有 (" _to have, to be_ ") → " _none-have, none-be_ " → " _nothing_ ".

## 烏有 as _kun'yomi_ : _izukunzo aran'ya_

Addressing the latter portion of your question, いずくんぞあらんや is provided as the
_kun'yomi_ or native Japanese reading of the Classical Chinese term 烏有. いずくんぞ
again has no relation to the " _crow_ " meaning of 烏, and あらんや implies the
opposite of the " _to have, to exist_ " meaning of 有, but the full _kun'yomi_
is related to the Classical Chinese meaning of the full phrase.

### The pieces: _izukunzo_

いずくんぞ is a contraction. Walking it back:

  * いずくんぞ
  * いづく + に + ぞ
  * いづこ (何【いづ】 " _which_ " + 処【こ】 " _place_ " → modern どこ) + に (locative particle) + ぞ (used in Classical Japanese after interrogatives to indicate non-specificity, apparently similar to the modern use of も as in どこにも)

いずくんぞ literally appears to mean " _wheresoever_ ". In practice, its meaning
was closer to " _why_ " (perhaps similar to archaic English " _wherefore_ ").
The term mainly appears in Classical Japanese, in the _kundoku_ (native
Japanese recitation) of _kanbun_ (works written in [broadly speaking]
Classical Chinese). いずくんぞ was used to introduce a supposition as part of a
rhetorical question with an implied negative answer: " _why would [you think
X, it be X, etc.] (because actually that's not the case)._ " One usage example
given in Shogakukan's _Kokugo Dai Jiten_ is いずくんぞ知【し】らん: " _why would
[someone] know it (when they probably don't)._ "

### The pieces: _aran'ya_

あらんや is similarly a contraction.

  * あらんや
  * あらむ (有る " _to be_ " + supposition auxiliary む → modern あろう " _is it?, would it be?_ ") + や (question particle)

In Classical Japanese, the -む + や construction was used in rhetorical
questions where the answer is assumed to be "no", somewhat like the English
construction " _would it be X_ " with intonation used to indicate a meaning of
" _it isn't X_ ".

### The full _kun'yomi_ phrase

Putting it back together then, いずくんぞあらんや ultimately parses out to " _why would
there be anything?_ ", intending " _there isn't anything_ " → " _nothing_ ".




## 烏有 as _on'yomi_ : _uyū_

As others have noted in the question comments, 烏有 read as _uyū_ derives from
Classical Chinese. Its origins there appear to be based on 烏 (not " _crow_ "
here, instead used phonetically in Middle Chinese as an interrogative and
negative indefinite pronoun, as noted by snailboat and Derpius in the comments
above) + 有 (" _to have, to be_ ") → " _none-have, none-be_ " → " _nothing_ ".

## 烏有 as _kun'yomi_ : _izukunzo aran'ya_

Addressing the latter portion of your question, いずくんぞあらんや is provided as the
_kun'yomi_ or native Japanese reading of the Classical Chinese term 烏有. いずくんぞ
again has no relation to the " _crow_ " meaning of 烏, and あらんや implies the
opposite of the " _to have, to exist_ " meaning of 有, but the full _kun'yomi_
is related to the Classical Chinese meaning of the full phrase.

### The pieces: _izukunzo_

いずくんぞ is a contraction. Walking it back:

  * いずくんぞ
  * いづく + に + ぞ
  * いづこ (何【いづ】 " _which_ " + 処【こ】 " _place_ " → modern どこ) + に (locative particle) + ぞ (used in Classical Japanese after interrogatives to indicate non-specificity, apparently similar to the modern use of も as in どこにも)

いずくんぞ literally appears to mean " _wheresoever_ ". In practice, its meaning
was closer to " _why_ " (perhaps similar to archaic English " _wherefore_ ").
The term mainly appears in Classical Japanese, in the _kundoku_ (native
Japanese recitation) of _kanbun_ (works written in [broadly speaking]
Classical Chinese). いずくんぞ was used to introduce a supposition as part of a
rhetorical question with an implied negative answer: " _why would [you think
X, it be X, etc.] (because actually that's not the case)._ " One usage example
given in Shogakukan's _Kokugo Dai Jiten_ is いずくんぞ知【し】らん: " _why would
[someone] know it (when they probably don't)._ "

### The pieces: _aran'ya_

あらんや is similarly a contraction.

  * あらんや
  * あらむ (有る " _to be_ " + supposition auxiliary む → modern あろう " _is it?, would it be?_ ") + や (question particle)

In Classical Japanese, the -む + や construction was used in rhetorical
questions where the answer is assumed to be "no", somewhat like the English
construction " _would it be X_ " with intonation used to indicate a meaning of
" _it isn't X_ ".

### The full _kun'yomi_ phrase

Putting it back together then, いずくんぞあらんや ultimately parses out to " _why would
there be anything?_ ", intending " _there isn't anything_ " → " _nothing_ ".

