How to say "flat" in Japanese

Choosing the right word
  • 平らたいらJLPT N3approx.Common
    na-adjectiveCovers 'flat' in the physical sense: a surface that is level, even and smooth, with no bumps or slopes. You would use it of ground, roads and similar surfaces.
    あの山やまの頂上ちょうじょうは平たいらだ。↗
    The top of that mountain is flat.
  • 平たいひらたいJLPT N1approx.Common
    i-adjectivePhysical flatness again, but typically of an object's overall shape — flat and thin, like a flattened stone or box — where 平ら stresses the evenness of a surface such as ground.
    古代こだい人にんたちは地球ちきゅうは平ひらたいと信しんじていた。↗
    The ancients believed the earth was flat.
  • マンションJLPT N2approx.Common
    nounThe housing sense of 'flat': a condominium or apartment building, usually mid- or high-rise — the block of flats itself. For the individual dwelling you live in, the word is 部屋.
    私のおじはマンションに住すんでいる。↗
    My uncle lives in an apartment.
  • 部屋へやJLPT N5approx.Common
    nounThe 'flat' of 'my flat': the dwelling itself, not the building. Literally 'room', it is how you speak of the apartment where you live — 'come over to my flat'.
    私の部屋へやは4階かいにあります。↗
    My apartment is on the fourth floor.
  • 閑散かんさんCommon
    na-adjective, nounThe 'flat' of flat business: trade or activity that is slack and inactive, as in an off-season lull. Nothing to do with surfaces or housing — this is purely the commercial sense.

For physical flatness choose 「平ら」 for a level, even surface or 「平たい」 for a flat, thin object; for housing, 「マンション」 is the condominium building and 部屋 the flat you live in; 閑散 covers flat, slack business.

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

Japanese equivalents
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JLPT vocabulary levels are community estimates, not official (no official lists have been published since the 2010 revision).

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