What does 波長 mean?
波長 is a Japanese noun meaning “wavelength” in English. It is written as 波長 in kanji, はちょう in hiragana, and hachou in romaji. This word is part of JLPT N2 vocabulary.
Example sentence
ジャンスキーが観測したのは銀河系の中心核からの波長14.6mの電波であった。
What Jansky had observed was the 14.6m wavelength radio wave from the Milky Way's core.