How to say "signal" in Japanese

Choosing the right word
  • 信号しんごうJLPT N3approx.Common
    noun, suru verb, intransitive verbThe default word for signals such as traffic lights, railway signals, and electronic or transmitted signals. Use this for most technical senses of 'signal', including a signal a device sends or receives.
  • nounA loanword covering the same 'signal' sense. It often appears in technical, scientific, or specialized contexts, especially where the English term itself would be used; in everyday situations 信号 is usually the natural choice.
  • 電波でんぱJLPT N2approx.Common
    nounCovers 'signal' in the everyday sense of phone or radio reception, as in a weak or lost signal. Strictly it means radio waves, so for traffic lights or electronic signals you need a different word.
    彼かれの携帯電話けいたいでんわは他たの電話でんわを妨害ぼうがいする電波でんぱを出だした。↗
    His mobile phone produced radio emissions that interfered with other phones.
  • 合図あいずJLPT N3approx.Common
    noun, suru verb, transitive verb, intransitive verbUsed for a sign or cue given by a person, such as a wave of the hand or a nod. When 'signal' refers to human communication by gesture or agreed sign, this is the word to reach for.
    すぐにゴーの合図あいずをしてください。↗
    Give us the sign to go soon.
  • 通信つうしんJLPT N3approx.Common
    noun, suru verb, transitive verb, intransitive verbReally means correspondence, communication, or transmission rather than 'signal' itself. It is seldom the word you want for this English sense, though it appears in contexts involving the sending of information.
    彼かれは、無電むでんで通信つうしんを送おくった。↗
    He sent a message by wireless.

Use 信号 for lights and electronic signals, 電波 for phone or radio reception, 合図 for a gesture or cue between people, and 「シグナル」 as a loanword; 通信 means communication rather than signal.

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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