What's the name for 4-character Chinese character expressions like 천고마비 or 오리무중?

Question

The characters for 천고마비 mean 'sky high horse fat' and the word means 'autumn'.

오리무중 similarly means 'five ri(≈mile) fog centre' and can literally mean a very thick fog, or metaphorically, a state of ignorance or confusion.

I love these little (often semi metaphorical) constructions! Do they have a special name in Korean?

Answer 1

I wanna add some detailed explanations. If you only mean 4-characters Chinese character expressions, they are called 사자성어.

Many 사자성어 are 고사성어 and vice versa. But there are also many exceptions.

An example that belong to both of them:

• 조삼모사(朝三暮四) - The expression originated from an old story in China. There was a man who was breeding many monkeys. There were too many monkeys, so he declared in front of the, monkeys that he is going to give only 7 nuts a day - 3 for breakfast, 4 for dinner. The monkeys got angry, so he changed what he said. He declared again; now he is going to give them 4 for breakfast, 3 for dinner. Then monkeys were happy. 조삼모사 means 'fooling someone with a cheap trick'.

Here is an example of 고사성어 which doesn't have four letters. Some 고사성어 with only two or three letters are used widely, so even Koreans can't easily figure out that the word is a 고사성어.

• 모순(矛盾) - It means a spear and a shield, literally. There was a merchant who was selling spears and shields. He told people that his spear can pierce every shield and his shield can protect from every spear. One person in the audience asked him, 'What will happen if you try to pierce your shield with your spear?' The merchant ran away. 모순 means contradiction.

Some 사자성어 do not have such origin stories.

• 명명백백(明明白白) - It means 'extremely obvious'. It is just an emphasized expression of 명백, so there is no story from which the expression originated.

In short, all 4-letter Chinese character expressions are 사자성어. An expression with 2~6 letters with an origin story, is called 고사성어. They have a large intersection but are not 100% same.

Answer 2

They are called 사자성어 (四字成語), as Posh_Pumpkin said in the comment. 사자(四字) means four-letter. 성어(成語) means something like proverb, according to the dictionary, but I think it's only used in forms like 사자성어 or 고사성어.

고사성어 (故事成語) is something similar. 고사(故事) basically means things that happened long time ago, so 고사성어 means a proverb that originates from an old story. As far as I know, the majority of 고사성어 are 사자성어.

천고마비 is a 고사성어 (and 사자성어 too obviously) that has been passed on from way back in ancient China, where there were frequent attacks from the Huns in the fall. The Huns were nomadic people, and they rode horses. In order to carry out attacks, they fed their horses well. So when the sky became clear, and the horses were fattened, the ancient Chinese people knew it was fall, and prepared for attacks.