中空|ちゅうくうchuukuu[0]heiban (flat)

1. no-adjectivehollow
   虫むしに食い荒くいあらされて桃ももは中空ちゅうくうになっていた。↗

   The insect ate the peach hollow.
2. no-adjectivemid-air; air; sky

• Synonym空そらNeutralEveryday word for something with nothing inside; the most common choice in speech. 「中空」 instead highlights a hollow internal structure or being in mid-air.
• Related空からNeutralEveryday word for something with nothing inside; the most common choice in speech. 「中空」 instead highlights a hollow internal structure or being in mid-air.
• Related空きあきNeutralA vacancy or gap — a seat, room or slot that is not occupied, as in 「空き部屋」. The focus is on being unoccupied, not hollow inside.
• Related空っぽからっぽCasualColloquial for something completely empty, as in 「財布が空っぽ」. Describes an empty state rather than a hollow internal structure.
• Related空虚くうきょWrittenWritten/formal word for emptiness, often figurative for a hollow inner life or lack of substance; not used for hollow structures.
• Relatedがら空きがらあきCasualColloquial: a place left almost completely empty of people, as in 「電車ががら空き」. Describes deserted spaces, not hollow objects.
• RelatedがらんどうNeutralDescribes a space as bare and cavernous; originally the main hall of a temple. Carries a sense of vast emptiness.
• Related虚うろNeutralThe same word 「から」 as the first 空 above, also written 「虚」: empty, with nothing there. 「中空」 itself leans toward technical descriptions of hollow things.
• Antonym中実WrittenThe antonym: solid rather than hollow inside, the direct opposite of 「中空」. A written-style word that is not often used.

For something simply empty, use 「空」 or 「空っぽ」. For a hollow internal structure or being in mid-air, use 「中空」, as in 「中空構造」 and 「中空に浮かぶ」. For solid, use 「中実」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. そら。虚空こくう。空中くうちゅう。
2. 内部ないぶが空そらであること。