<p>I'd like to offer a slightly different perspective from the other answers, and suggest that the most important difference between the two is that 太陽 is a free word, whereas 日 is a bound morpheme, i.e. it cannot appear as an independent word.  Think of 太陽 as 'sun' and '日' as sol-.  Of course they are not word for word identical with the English forms, but the basic concept is, perhaps, somewhat similar. </p>

<p>I don't agree that 日 is more common as 'day' than as 'sun'; it is pretty much parallel with 月, which is both 'month' and 'moon', and it's really quite difficult to say which is more common.  The morphology of 'moon' is also somewhat similar to 'sun' in Chinese, except that 月 is free when it means 'month'. whereas when it means the celestial body, it is bound, and you need the form 月亮. (Correct me if I'm wrong!) </p>

<p>Historically, 日 was both sun and day. (天 was originally different from 日, consisting of two things: 一日and 一夜.) How 太陽 became the word for 'sun' is an interesting question. In a large number of dialects, especially in northern China, the word for sun is still 日頭. It seems that 日 kept its meaning as sun pretty much unchanged in these dialects. </p>

<p>太陽 seems to have been an astrological term for 'sun', with the moon identified as 太陰. Why did 太陽 win out and supplant 日 and all its variants, while 太陰 lost out completely? I'll award 5 *'s to the lexico-mane who can answer that one.</p>

CC BY-SA 3.0
2015-08-26T06:39:32.810Z
this one's the excellent answer
Marson Mao
CC BY-SA 3.0
2015-09-03T14:47:38.377Z
The common use of "太陽" as "sun" in daily context seems to be much related to the rise of 白話文, in which loads of terms/words (漢字詞語) were imported from Japan; and this includes new usages of existing chinese terms.
Henry HO
CC BY-SA 3.0
2015-08-25T11:54:23.193Z
2015-08-25T11:54:23.193Z
wpt
<p>The word used in modern Chinese is nearly always 太阳. In nearly all cases where in English you would use the word <code>sun</code> you can use 太阳. </p>

<p>The only exception I can think of is 向日葵, which means <code>sunflower</code>. There may be some other compounds words or derivative words (solar) that use 日 instead of 太阳, but I think generally, it would be would be pretty safe to use 太阳.</p>

<p>日 in modern Chinese means <code>day</code> or <code>daytime</code> or a <code>certain date/time</code>.</p>

CC BY-SA 3.0
2015-08-25T09:17:42.743Z
2015-08-25T09:17:42.743Z
Ringil
<p>As a Chinese, I feel 日 is usually used in ancient Chinese or modern Chinese vocabularies from the old days, we use 日 in modern Chinese is because in some cases, we want to simplify the word, like 日光浴，basically means tanning, 日光 means sunshine, and 阳光 means sunshine too. </p>

<p>So, if you say 太阳 in modern Chinese, in most cases, you're exactly fine. however, if you use 太阳 for everything related to sun, that will be too nerdy and scientific...  for example, we usually use 太阳光 when we write some technical articles about analysis on radiation of sunlight, in this case, we may use 太阳光 for sunlight.</p>

CC BY-SA 3.0
2015-08-27T15:47:04.240Z
2015-08-27T15:47:04.240Z
X-Spirit
<p>日 both means <em>sun</em> and <em>day</em> (and is short for <em>Japan</em>, etc.), but the most common meaning of 日 is <em>day</em> or <em>daytime</em>. </p>

<p>E. g. :</p>

<ul>
<li>每日 every day, daily</li>
<li>日志 journal, log</li>
<li>昨日 yesterday</li>
<li>日报 daily (paper)</li>
<li>and many-many more.</li>
</ul>

<p>The only examples I can think of where 日 denotes <em>the Sun</em> and not <em>day</em>/<em>daily</em> are:</p>

<ul>
<li>日出 (rì chū) sunrise</li>
<li>旭日 (xùrì) rising sun</li>
<li>烈日 (lièrì) scorching sun </li>
<li>红日 (red) sun</li>
<li>etc.</li>
</ul>

<p>As you can see, the <em>day</em> meanings are derived from the <em>sun</em> meaning, as 日 originally denoted the Sun since earliest times. But the meaning later shifted toward <em>day</em>/<em>daily</em> and as you can see most compounds with 日 now translate as something with <em>day</em>.</p>

<p>太阳 on the other hand unambiguously refers to <em>the Sun</em> as a celestial body, both in scientific and everyday usage. In compounds it sometimes translates as <em>solar</em> but I think that is no surprise for an Italian [if my guess is correct]. </p>

CC BY-SA 3.0
2015-08-25T09:19:14.470Z
2015-08-25T09:44:16.870Z
2015-08-25T09:44:16.870Z
imrek
<p>What is the difference between 太阳 (tài yáng) and 日 (rì) for "sun"?
Are they used in different contexts or are they interchangeable?</p>

CC BY-SA 3.0
2015-08-25T09:39:58.160Z
And for good measure there is also 太阳日, a solar day!
Pedroski
CC BY-SA 3.0
2015-08-26T06:14:10.623Z
Note: as @hyouuu pointed out, 日 (rì) is commonly used as a cursing verb. But this doesn't address the question...
Starnuto di topo
CC BY-SA 3.0
2015-08-26T07:36:41.577Z
Note that 日 might be considered a cursing verb only in some branches of Chinese such as Mandarin. In other branches like Cantonese it solely means "sun": [日頭](https://en.wiktionary.org/wiki/%E6%97%A5%E9%A0%AD) morning/sun
Derek 朕會功夫
CC BY-SA 3.0
2015-08-26T08:53:05.723Z
yea let me move it here... Just FYI 日 is commonly used as a cursing verb..
hyouuu
<difference>
Usage of word "sun": 太阳 (tài yáng) vs 日 (rì)
# Usage of word "sun": 太阳 (tài yáng) vs 日 (rì)

(Asked by: username_0 on 2015-08-25)

What is the difference between 太阳 (tài yáng) and 日 (rì) for "sun"?
Are they used in different contexts or are they interchangeable?

**Tags:** difference

> **Comments:**
> **username_1**: And for good measure there is also 太阳日, a solar day!  
> **username_0**: Note: as @username_3 pointed out, 日 (rì) is commonly used as a cursing verb. But this doesn't address the question...  
> **username_2**: Note that 日 might be considered a cursing verb only in some branches of Chinese such as Mandarin. In other branches like Cantonese it solely means "sun": [日頭](https://en.wiktionary.org/wiki/%E6%97%A5%E9%A0%AD) morning/sun  
> **username_3**: yea let me move it here... Just FYI 日 is commonly used as a cursing verb..  

---

## 4 answers

### Answer by username_9 on 2015-08-25. Score: 10 | Accepted answer

日 both means *sun* and *day* (and is short for *Japan*, etc.), but the most common meaning of 日 is *day* or *daytime*.

E. g. :

* 每日 every day, daily
* 日志 journal, log
* 昨日 yesterday
* 日报 daily (paper)
* and many-many more.

The only examples I can think of where 日 denotes *the Sun* and not *day*/*daily* are:

* 日出 (rì chū) sunrise
* 旭日 (xùrì) rising sun
* 烈日 (lièrì) scorching sun
* 红日 (red) sun
* etc.

As you can see, the *day* meanings are derived from the *sun* meaning, as 日 originally denoted the Sun since earliest times. But the meaning later shifted toward *day*/*daily* and as you can see most compounds with 日 now translate as something with *day*.

太阳 on the other hand unambiguously refers to *the Sun* as a celestial body, both in scientific and everyday usage. In compounds it sometimes translates as *solar* but I think that is no surprise for an Italian [if my guess is correct].


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### Answer by username_4 on 2015-08-25. Score: 15

I'd like to offer a slightly different perspective from the other answers, and suggest that the most important difference between the two is that 太陽 is a free word, whereas 日 is a bound morpheme, i.e. it cannot appear as an independent word. Think of 太陽 as 'sun' and '日' as sol-. Of course they are not word for word identical with the English forms, but the basic concept is, perhaps, somewhat similar.

I don't agree that 日 is more common as 'day' than as 'sun'; it is pretty much parallel with 月, which is both 'month' and 'moon', and it's really quite difficult to say which is more common. The morphology of 'moon' is also somewhat similar to 'sun' in Chinese, except that 月 is free when it means 'month'. whereas when it means the celestial body, it is bound, and you need the form 月亮. (Correct me if I'm wrong!)

Historically, 日 was both sun and day. (天 was originally different from 日, consisting of two things: 一日and 一夜.) How 太陽 became the word for 'sun' is an interesting question. In a large number of dialects, especially in northern China, the word for sun is still 日頭. It seems that 日 kept its meaning as sun pretty much unchanged in these dialects.

太陽 seems to have been an astrological term for 'sun', with the moon identified as 太陰. Why did 太陽 win out and supplant 日 and all its variants, while 太陰 lost out completely? I'll award 5 \*'s to the lexico-mane who can answer that one.

> **Comments:**
> **username_5**: this one's the excellent answer  
> **username_6**: The common use of "太陽" as "sun" in daily context seems to be much related to the rise of 白話文, in which loads of terms/words (漢字詞語) were imported from Japan; and this includes new usages of existing chinese terms.  

---

### Answer by username_7 on 2015-08-25. Score: 3

The word used in modern Chinese is nearly always 太阳. In nearly all cases where in English you would use the word `sun` you can use 太阳.

The only exception I can think of is 向日葵, which means `sunflower`. There may be some other compounds words or derivative words (solar) that use 日 instead of 太阳, but I think generally, it would be would be pretty safe to use 太阳.

日 in modern Chinese means `day` or `daytime` or a `certain date/time`.


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### Answer by username_8 on 2015-08-27. Score: 1

As a Chinese, I feel 日 is usually used in ancient Chinese or modern Chinese vocabularies from the old days, we use 日 in modern Chinese is because in some cases, we want to simplify the word, like 日光浴，basically means tanning, 日光 means sunshine, and 阳光 means sunshine too.

So, if you say 太阳 in modern Chinese, in most cases, you're exactly fine. however, if you use 太阳 for everything related to sun, that will be too nerdy and scientific... for example, we usually use 太阳光 when we write some technical articles about analysis on radiation of sunlight, in this case, we may use 太阳光 for sunlight.


---

