合図（あいず、aizu）
- signal

The Japanese word 合図 (あいず) primarily means "signal," "sign," or "cue." It refers to a gesture, sound, or other indication that communicates information or prompts an action. It can be a visual sign, an auditory cue, or even a pre-arranged action. 合図s are used to coordinate activities, give instructions, or convey information in a concise manner. The purpose of a 合図 is to communicate effectively, often to avoid the need for lengthy explanations.

⚫︎ 合図でスタートする。 Translation: Start with a signal. ⚫︎ 手の合図で静かにしてください。 Translation: Please be quiet with a hand signal. ⚫︎ 彼らは危険の合図を送った。 Translation: They sent a signal of danger.

You use 合図 when you want to talk about signals or cues used in various contexts. It's appropriate for formal and informal situations. ⚫︎ It's often used when describing actions that follow a predetermined cue, such as a traffic signal (traffic light), a starting signal in a race, or a hand signal to communicate directions. ⚫︎ It can also refer to signs used to communicate a warning or convey information, such as signals of danger. ⚫︎ The type of 合図 can be specified by additional words: 手(て)の《合図》 (hand signal), 音楽(おんがく)の《合図》 (musical cue), etc.

⚫︎ The word is typically written in kanji as 合図 or in hiragana as あいず. ⚫︎ Katakana is not used for this word. ⚫︎ The okurigana (送りがな), the hiragana that follows the kanji, is always 図.

⚫︎ サイン (sain) - Sign (loanword from English). This is a general term for a sign. ⚫︎ シグナル (shigunaru) - Signal (loanword from English). Similar to サイン, but perhaps implying a more technological or formal signaling method. ⚫︎ 目印(めじるし) (mejirushi) - Mark, sign, landmark. This often refers to a physical marker or indication. ⚫︎ 合図(あいず): 合図 in kanji.

There aren't direct antonyms for 合図 in the sense of a single word. The concept of "no signal" or "lack of a cue" would be expressed differently depending on the context. For instance: ⚫︎ 無言(むごん) (mugon) - Silence, speechlessness. ⚫︎ 無音(むおん) (muon) - Silence, no sound.

先生(せんせい)は授業(じゅぎょう)を始める《合図としてベルを鳴(な)らしました。》 ・Translation: The teacher rang the bell as a signal to start the class. ・Explanation: This sentence explains how a bell is used as a signal to indicate the beginning of a class.

彼は出発(しゅっぱつ)の《合図を待(ま)っていました。》 ・Translation: He was waiting for the signal to depart. ・Explanation: This sentence describes someone waiting for a cue, probably for a journey or some other starting activity.

The word 合図 is formed from two kanji: 合(あ) meaning "to fit," "to join," "to combine," or "to meet" and 図(ず) meaning "drawing," "figure," "plan," or "chart". Together, they indicate the joining or meeting of an action or event with a prearranged signal. The concept is that the action "fits" or corresponds to the "drawing" or "plan" signaled by the 合図.