空くう洞どう

く

う

ど

う

Common wordFreq.FrequencyTop 20,000

Meanings

1

noun

cavity; hollow; cavern

A hollow space inside something, ranging from a small cavity in a wall or tooth to a larger underground cave-like space.

壁かべの中なかに小ちいさな空

くう

洞どう

が

あっ

た

。

There was a small cavity inside the wall.

調ちょう査さで地ち下かに大おおきな空くう洞どうが見みつかった。

The survey found a large cavernous hollow underground.

2

noun which may take the genitive case particle 'no'

hollow; cavernous

Used before の to describe something whose inside is hollow or empty, as in 空洞の pipe, trunk, or structure.

空くう洞どうのパイプは見みた目めより軽かるい。
A hollow pipe is lighter than it looks.
その古ふるい木きは幹みきの中なかが空くう洞どうの状じょう態たいだった。
The old tree's trunk was hollow inside.

Usage patterns

〈場ば所しょ〉に空くう洞どうがあるthere is a cavity/hollow space in ~
木きの中なかに空くう洞どうがあった。
There was a hollow inside the tree.
空くう洞どうができるa cavity forms
虫むし歯ばが進すすむと歯はに空くう洞どうができる。
As tooth decay progresses, a cavity forms in the tooth.
空くう洞どうの〈物もの〉a hollow ~ (something empty inside)
空くう洞どうのパイプを使つかって音おとを響ひびかせる。
They use a hollow pipe to make the sound resonate.

Kanji

空empty, sky, void
洞den, cave, excavation

Related words· 7

穴あなN3sense 1
穴 is the everyday word for any hole or opening, while 空洞 specifically emphasizes an empty space inside something solid.
洞どう窟くつ sense 1
洞窟 refers specifically to a natural cave, whereas 空洞 can describe any hollow space, from a small cavity to a cave-like void.
中ちゅう空くう sense 2
中空 is often used technically or adjectivally to describe something hollow inside, while 空洞 is the noun naming the hollow space itself.
虚うろ
空洞 is a more technical or formal term for a cavity or hollow space, while 虚（うろ）is the everyday word for a natural hollow, especially in a tree.

Show 3 more

虚うつろN1
空洞 is a technical or formal term for a physical hollow or cavity, while 虚ろ can describe the same physical emptiness in a more literary, evocative way.
洞ほら
空洞 is a more formal or technical term for an internal cavity or hollow space, often used in scientific contexts, whereas 洞 is a plainer, more everyday word.
空くう虚きょN1
空洞 refers to a literal hollow cavity, such as inside a tree or the ground, whereas 空虚 can describe both physical and abstract emptiness.

Word family

空くう洞どう化か
hollowing out; making hollow; making meaningless · deindustrialization; hollowing out of industry
超ちょう空くう洞どう
void; cosmic void
空くう洞どう共きょう振しん器き
cavity resonator; microwave resonance cavity

Etymology

A Sino-Japanese compound written with 空, associated with emptiness, and 洞, associated with caves or hollows; the exact historical development is not specified.