波長(はちょう)

はちょう
noun
wavelength
technical
1. wavelength
The distance between successive crests of a wave, used in physics to describe light, sound, and other wave phenomena.
赤(あか)い光(ひかり)は波長(はちょう)が長(なが)い。
Red light has a long wavelength.
紫外線(しがいせん)は短(みじか)い波長(はちょう)の光(ひかり)である。
Ultraviolet light is light with a short wavelength.
電磁波(でんじは)の波長(はちょう)は種類(しゅるい)によって大(おお)きく異(こと)なる。
The wavelength of electromagnetic waves varies greatly depending on the type.
2. wavelength; compatibility; being on the same page
Used figuratively to describe how well two people's personalities, thinking styles, or communication mesh together.
彼女(かのじょ)とは波長(はちょう)が合(あ)う。
I'm on the same wavelength as her.
初(はじ)めて会(あ)ったのに、波長(はちょう)がぴったり合(あ)った。
Even though we met for the first time, we were perfectly in sync.
あの人(ひと)とはどうも波長(はちょう)が合(あ)わなくて、話(はなし)がかみ合(あ)わない。
I just can't seem to get on the same wavelength as that person — our conversations never quite click.

Has both a scientific and a figurative meaning. The figurative sense — describing interpersonal compatibility — is extremely common in everyday Japanese and often more frequently encountered than the physics sense.

Common collocations

Usage

The figurative expression 波長(はちょう)が合(あ)う describes a natural, effortless compatibility between people — the feeling that conversation and interaction flow smoothly without conscious effort. It is a very natural and idiomatic expression, not stiff or technical sounding.

Similar words

Related Words

Compare: 気(き)が合(あ)う (to get along well)
Compare: 相性(あいしょう)がいい (good compatibility)
Compare: 周波数(しゅうはすう) (frequency (of waves, radio signals, sound))
Compare: 波動(はどう) (wave motion)
Compare: 波形(はけい) (waveform)
general
Added 2026.5.7 20:10 · Revised 2026.9.2 13:02
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