シグナル

Common collocations

• シグナルを送(おく)る / 出(だ)す: to send/emit a signal
• シグナルを受(う)け取(と)る: to receive a signal
• 危険(きけん)シグナル: danger signal
• 開始(かいし)のシグナル: start signal

Similar words

• 信号(しんごう): signal, traffic light (more common in everyday use for traffic signals)
• 合図(あいず): signal, cue (typically a gesture or agreed-upon sign between people)
• サイン: sign, signal (also means signature or autograph)

シグナル tends to be used in more technical, scientific, or metaphorical contexts. For traffic lights, 信号(しんごう) is the standard term, not シグナル.