空 (kōng): empty, sky

空 (kōng) is a Chinese character meaning “empty, sky.” Classified as HSK Level 3 (HSK 3.0 Standard, CLEC 2022), it is composed of 穴 (semantic) and 工 (phonetic). It ranks #272 in character frequency (SUBTLEX-CH corpus).

Etymologically derived, 空 cave. Its radical form 穴 (cave) appears in many related characters such as 穿 (chuān, to wear, 穿透), 突 (tū, sudden), 究 (jiū, research).

Spoken pronunciation

Definitions

  1. empty, sky

Etymology & Origin

空

pictophoneticcave

Decomposition: ⿱穴工 (layout: top-bottom)

Stroke Order

1
2
3
4
5
6
7
8

Practice writing 空 with real-time feedback — trace each stroke in the correct order and build muscle memory in the HanziFeed app.

Words & Compounds

HSK Vocabulary with 空

WordPinyinMeaningHSK
空间nounkōng jiānspace5
空气nounkōng qìair4
太空nountài kōngouter space6
天空nountiān kōngsky5
空中noun/adjectivekōng zhōngin the sky5
航空verbháng kōngaviation6
空调nounkōng tiáoair conditioning3
空地nounkōng dìair-to-surface (missile)6
空闲adjective/nounkòng xiánleisure6

Common Compounds

WordPinyinMeaning
有空verbyǒu kòngto have time (to do sth)
空军nounkōng jūnair force
时空nounshí kōngtime and place
空白nounkòng báiblank space
空手verbkōng shǒuempty-handed
空虚adjectivekōng xūhollow
太空船nountài kōng chuánspaceship
上空shàng kōngthe skies above a certain place
凭空píng kōngbaseless (lie)
空姐nounkōng jiěstewardess
空缺nounkòng quēvacancy
抽空verbchōu kòngto find the time to do sth
空袭nounkōng xíto make an air raid
高空noungāo kōnghigh altitude
空洞nounkōng dòngcavity
112
Total compounds
52
As first character
42
As last character
6
As middle character

空 appears in 112 compound words: 52 as the first character, 42 as the last, and 6 in a middle position. Compound statistics computed from SUBTLEX-CH and HSK 3.0 vocabulary data.

Strongest Collocations

Characters that most frequently co-occur with 空 in natural Chinese text, ranked by NPMI (Normalized Pointwise Mutual Information) — a statistical measure of association strength.

监jiān
0.697126,250 co-occurrences
太tài
0.641187,486 co-occurrences
视shì
0.637126,762 co-occurrences
航háng
0.630196,395 co-occurrences
防fáng
0.47436,472 co-occurrences
气qì
0.46323,772 co-occurrences
间jiān
0.45779,018 co-occurrences
隙xì
0.4543,454 co-occurrences
军jūn
0.45361,632 co-occurrences
悟wù
0.4448,521 co-occurrences

Idioms & Chengyu (45)

赤手空拳chìshǒukōngquánHSK 7+

bare-handed and unarmed; without any reliance; without anything to rely on

phrase
翻空出奇fān kōng chū qíHSK 4+

to overturn empty convention, and display originality (idiom); new and different ideas

phrase
高空弹跳gāokōng tántiàoHSK 4+

bungee jumping

noun
海阔天空hǎikuòtiānkōngHSK 6+

the sea and the sky is expansive and boundless; bold and unconstrained

phrase
航空公司hángkōng gōngsīHSK 4+

airline

noun
航空母舰hángkōng mǔjiànHSK 7+

aircraft carrier

noun
空洞无物kōngdòngwúwùHSK 5+

utter lack of substance; devoid of content

phrase
空腹高心kōng fù gāo xīnHSK 7+

ambitious despite a lack of talent (idiom)

phrase
空谷足音kōng gǔ zú yīnHSK 7+

(lit.) the sound of footsteps in a deserted valley (idiom); (fig.) sth hard to come by; sth wonderful and rare

phrase
空话连篇kōnghuàliánpiānHSK 4+

endless pages of empty verbiage; long talk with no real substance

phrase
空空荡荡kōng kōng dàng dàngHSK 7+

deserted

phrase
空空洞洞kōng kōng dòng dòngHSK 5+

empty; hollow; lacking in substance

phrase

Showing 12 of 45 idioms containing 空.

Example Sentences

AI-Generated

这个房间空荡荡的,什么家具都没有。

Zhè gè fángjiān kōngdàngdàng de, shénme jiājù dōu méiyǒu.

This room is empty; there is no furniture at all.

百度新闻Feb 2026

视频丨空间站的年夜饭都有什么?听航天员报菜名收祝...

shì pín 丨 kōng jiān zhàn de nián yè fàn dū yǒu shén má ? yǐn háng tiān yuán bào cài míng shōu zhù . . .

Video 丨What's for New Year's Eve dinner on the space station? The astronauts will be able to tell you the names of the dishes and receive congratulations...

百度新闻Feb 2026

请停留3秒 为这5位空军勇士献花!今天是万家团圆的..

qǐng tíng liú miǎo wéi zhè wèi kōng jūn yǒng shì xiàn huā ! jīn tiān shì mò jiā tuán yuán de . .

Please stay for 3 seconds to lay flowers for these 5 Air Force warriors! Today is the day of family reunion...

百度新闻Feb 2026

大湾区航空飞往台北航班遇大雾盘旋后折返,航司回应:...

dà wān ōu háng kōng fēi wǎng tái běi háng bān yù dà wù pán xuán hòu shé fǎn , háng sī huí yīng . . .

A Greater Bay Area Airlines flight to Taipei encountered heavy fog, circled, and then returned. The airline responded:...

百度新闻Feb 2026

抖音集团李亮:炒作“字节是恒科的最大空头”很荒唐也..

dǒu yīn jí tuán lǐ liàng chǎo zuò zì jié shì héng kē de zuì dà kōng tóu hěn huāng táng yě . .

Li Liang of Douyin Group: Hyping "ByteDance is Hengke's biggest short seller" is utterly absurd and...

百度新闻Feb 2026

美空军宣布新“空军一号”总统专机将启用新涂装...

měi kōng jūn xuān bù xīn kōng jūn yī háo zǒng tǒng zhuān jī jiāng qǐ yòng xīn tú zhuāng . . .

The U.S. Air Force announced that the new "Air Force One" presidential aircraft will feature a new livery...

Tatoeba

你怎么在太空里找到食物?

Nǐ zěnme zài tàikōng lǐ zhǎodào shíwù?

How do you find food in outer space?

Tatoeba

顺便问一句,你今晚有空吗?

Shùnbiàn wèn yījù, nǐ jīnwǎn yǒu kòng ma?

By the way, are you free tonight?

Tatoeba

小姐,今天晚上有没有空房间?

Xiǎojie, jīntiān wǎnshang yǒuméiyǒu kōngfángjiān?

Miss, are there any available rooms for tonight?

Tatoeba

您空闲时间喜欢做什么?

Nín kòngxián shíjiān xǐhuan zuò shénme?

What do you like to do in your free time?

Character Family

Semantic Family — Characters sharing the 穴 (cave) component

Frequently Asked Questions

What does 空 (kōng) mean in Chinese?
空 (kōng) primarily means "empty, sky." It is classified as HSK Level 3, making it a beginner-level character. It ranks #272 in character frequency.
What's the difference between 空 and 饱?
空 (kōng) and 饱 (bǎo) are often confused. antonym. The key distinguishing feature: 空 (empty) vs 饱 (full).
How many strokes does 空 have?
空 is written with 8 strokes. The correct stroke order matters for recognition and handwriting speed — practice with the animated guide above to build proper technique.
What is the radical of 空?
The radical associated with 空 is 穴 (cave). This radical appears in many characters related to cave.
What are the components of 空?
空 is composed of: 穴 (semantic), 工 (phonetic). Its IDS decomposition is ⿱穴工 with a top-bottom layout. Understanding the components helps with both memorization and recognizing related characters.
What are common words containing 空?
Common words with 空 include: 空间 (kōng jiān, "space"); 空气 (kōng qì, "air"); 太空 (tài kōng, "outer space"); 有空 (yǒu kòng, "to have time (to do sth)"); 天空 (tiān kōng, "sky"). There are over 112 compound words containing this character.
Is 空 the same in simplified and traditional Chinese?
Yes, 空 is written the same way in both simplified and traditional Chinese.

Practice writing 空 with real-time feedback

Trace stroke sequences, hear spoken pronunciation, and build lasting retention with spaced repetition in the HanziFeed app.

Character data sourced from Unihan (Unicode Consortium), SUBTLEX-CH frequency corpus (Cai & Brysbaert, 2010), and Make Me a Hanzi (stroke data). Collocation strength measured via NPMI (Normalized Pointwise Mutual Information). Verified by the HanziFeed linguistics team.

HSK classification follows the HSK 3.0 Standard (Center for Language Education and Cooperation, CLEC, 2022 revision). Idiom data from Wiktionary (CC BY-SA 3.0).

Data last verified: March 2026.