<p>Radicals are not building blocks of characters, they're dictionary entry organisation headers. They're equivalent to the first letter in an English word. The radicals are <em>chosen</em> so that some characters are easily and obviously grouped under these headers, but some radicals are very arbitrary (see e.g. <a href="https://en.wikipedia.org/wiki/Radical_4" rel="nofollow noreferrer">Radical 4</a> and the characters grouped under it).</p>

<p>The optimisation of a Chinese dictionary (at least the Kangxi dictionary) is concerned about how to organise 50,000 characters whilst choosing the number of appropriate dictionary headings (<em>radicals</em>) to split these 50,000 characters under.</p>

<p>In this light,「烏」is less suitable than「鳥」as a header, because many more characters are clearly grouped under「鳥」rather than「烏」. However, if one looks at <em>Shuowen Jiezi</em>, <a href="https://en.wikipedia.org/wiki/List_of_Shuowen_Jiezi_radicals" rel="nofollow noreferrer">which has 540 radicals</a> (as opposed to Kangxi's 214), one has more leeway in including radicals; indeed, <em>Shuowen</em> has「烏」as a radical.</p>

CC BY-SA 4.0
2019-04-19T19:41:14.057Z
2019-04-19T19:41:14.057Z
dROOOze
<p>烏 specifically referring to 'crow' </p>

<p>鳥 referring to 'bird' in general. </p>

<p>There are many 'bird' related characters, but I don't know any 'crow' related character</p>

<p>鴨(duck)、鵝(goose)、鶴(crane)、鷹(eagle)、鴉(crow) are all bird, but only 鴉 is crow</p>

<p><em>烏 also means 'black' because all crows are black, we even have an idiom '天下烏鴉一般黑' pointing out this fact</em></p>

CC BY-SA 4.0
2019-04-19T18:06:10.547Z
2019-04-20T02:15:19.443Z
2019-04-20T02:15:19.443Z
Tang Ho
<p>烏, <em>wū</em>, crow, 10 strokes, 灬 radical<br>
鳥, <em>niǎo</em>, bird, 11 strokes, 鳥 radical</p>

<p>All the way since at least seal script, <a href="https://en.m.wiktionary.org/wiki/File:%E9%B3%A5-seal.svg" rel="nofollow noreferrer">鳥</a> seems like just <a href="https://en.m.wiktionary.org/wiki/File:%E7%83%8F-seal.svg" rel="nofollow noreferrer">烏</a> with an additional stroke. They both describe birds in one way or another. Why was 烏 not used as the building block, as a separate radical, or even as a –1 stroke variant of 鳥?</p>

<etymology><radicals><strokes>
How did 鳥 end up a Kangxi radical but not 烏?
# How did 鳥 end up a Kangxi radical but not 烏?

(Asked by: username_0 on 2019-04-19)

烏, *wū*, crow, 10 strokes, 灬 radical  
鳥, *niǎo*, bird, 11 strokes, 鳥 radical

All the way since at least seal script, [鳥](https://en.m.wiktionary.org/wiki/File:%E9%B3%A5-seal.svg) seems like just [烏](https://en.m.wiktionary.org/wiki/File:%E7%83%8F-seal.svg) with an additional stroke. They both describe birds in one way or another. Why was 烏 not used as the building block, as a separate radical, or even as a –1 stroke variant of 鳥?

**Tags:** etymology, radicals, strokes

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## 2 answers

### Answer by username_1 on 2019-04-19. Score: 3

Radicals are not building blocks of characters, they're dictionary entry organisation headers. They're equivalent to the first letter in an English word. The radicals are *chosen* so that some characters are easily and obviously grouped under these headers, but some radicals are very arbitrary (see e.g. [Radical 4](https://en.wikipedia.org/wiki/Radical_4) and the characters grouped under it).

The optimisation of a Chinese dictionary (at least the Kangxi dictionary) is concerned about how to organise 50,000 characters whilst choosing the number of appropriate dictionary headings (*radicals*) to split these 50,000 characters under.

In this light,「烏」is less suitable than「鳥」as a header, because many more characters are clearly grouped under「鳥」rather than「烏」. However, if one looks at *Shuowen Jiezi*, [which has 540 radicals](https://en.wikipedia.org/wiki/List_of_Shuowen_Jiezi_radicals) (as opposed to Kangxi's 214), one has more leeway in including radicals; indeed, *Shuowen* has「烏」as a radical.


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### Answer by username_2 on 2019-04-19. Score: 0

烏 specifically referring to 'crow'

鳥 referring to 'bird' in general.

There are many 'bird' related characters, but I don't know any 'crow' related character

鴨(duck)、鵝(goose)、鶴(crane)、鷹(eagle)、鴉(crow) are all bird, but only 鴉 is crow

*烏 also means 'black' because all crows are black, we even have an idiom '天下烏鴉一般黑' pointing out this fact*


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