How to say "inside" in Japanese

• 中なかJLPT N5approx.Common
  nounThe general word for the inside of a physical space or object such as a box or a room; the default choice when you simply mean the inside of something.
  彼かれは自分じぶんのお金かねを全部ぜんぶ箱ばこの中なかに入いれた。↗

  He put all his money in the box.
• うちJLPT N4approx.Common
  noun, adverbIts main use is 'within' — a period of time or a range within which something happens, or a group considered from within — rather than the inside of a physical object.
• 内側うちがわCommon
  no-adjectiveThe inner side of something that has an inside and an outside: the side facing inward rather than the outer side. Typical of edges and boundaries, such as the inner side of a wall.
  ドアは内側うちがわから鍵かぎがかかっていた。↗

  The door was locked from within.
• 内部ないぶJLPT N1approx.Common
  no-adjectiveThe interior of something taken as a whole: the inside of a building, the internal parts of a machine, or matters internal to an organization.
  この図解ずかいは地球ちきゅうの深ふかい内部ないぶを示しめしている。↗

  The illustration shows the deep interior.
• 内面ないめんCommon
  nounThis is seldom the word for the physical inside of an object; it refers to a person's inner self — character and feelings — as opposed to outward appearance.

Use 中 for the inside of everyday things, 「うち」 for 'within' a span or group, 内側 for the inner side of something, 内部 for the interior of buildings or organizations, and 内面 for a person's inner self.

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

• 中なかinside
• うちinside
• 内側うちがわinside
• 内部ないぶinterior
• 内面ないめんinside
• 圏内けんないinside (a region, area, etc.)
• インサイドinside
• 庫内こないinside (a refrigerator, warehouse, etc.)
• 内方ないほうinside
• 内辺ないへんinside
• 内面的ないめんてきinner
• 内々うちうちprivate
• インin
• 裏うらlining
• 腹はらinside
• あんfilling