What's the difference between 词典, 辞典, and 字典?

Question

I don't think they are necessarily different kinds of dictionaries, but is there a subtle distinction? Or maybe their etymologies?

Answer 1

字典 means dictionary of characters. A common 汉字字典 should contain ~8000 entries for each Chinese character. In each character entry, it's often to see example words or short phrases using that character. So, it's common to see a 汉字字典 is used as a 汉语词典.

词典 means dictionary of words. So, each entry of a 汉语词典 is a word. Generally 汉语词典 is sorted in alphabetic order in Chinese characters, so it's common to see a 汉语词典 is used as a 汉字字典.

So, in China, there's not too much difference between 汉字字典 and 汉语词典. But the book of 汉语词典 is mostly thicker then 汉字字典.

辞典 means dictionary of phrases. Generally, 辞 may refer to some famous, well known phrases said by some dead guys or famous man. Well, like I've said it's not too much differences between 词典 and 辞典, but a book of 汉语辞典 is mostly thicker then a 汉语词典. You can also expect that a 汉语大辞典 is thicker then a 汉语辞典.

In English, it will be something like:

English 字典： (26 entries)

A    This is the first letter.
B    This is the second letter.
...
Z    This is the last letter.

English 词典:

A        Indefinite article. Also the first letter. e.g. a cat.
Apple    A kind of fruit. Green or red.
Cat      A white animal. two ears, four legs.
...

English 辞典:

Rain cats and dogs: A very big rain. Its rain drop is as big as cat or dog.

(Most 汉语辞典s include words and characters entries as well.)

Answer 2

The difference between 字典 and the other two is clear enough; the Baidu page on 字典 describes it as follows:

在西方，是没有字典的概念，全是中国独有的。 字典收字为主，亦会收词。词典或辞典收词为主，也会收字。
In the West, there is no concept of a "字典"; it is unique to China. A "字典" aims to collect 字, though it also collects words. A 词典 or 辞典 aims to collect words, though it also collects characters.

Non-Chinese languages lack a distinction between words and characters; Chinese differentiates between a 字典 and a 词典 because they have different goals.

The difference between 词典 and 辞典 is more subtle. A neither sourced nor particularly scholarly Baidu post gives the following:

词典，比字多了一层：组词和释义；辞典，是在字典和词典的基础上增加了词的使用方法.
A 词典 is one level deeper than a 字典: compound words and meanings; a 辞典 adds usage notes to the foundation of the 字典 and 词典.

(This same post claims that the main function of a 字典 is to provide pronunciation and writing information for characters.)

Answer 3

词（辞）典 is for compound words, eg 成语词典、汉语词典、etc.

字典 is for Chinese characters and meanings, focus on character's meaning, may also contain related compound words.