The kanji character 約 generally conveys the idea of "promise," "approximately," "to bind," or "to reduce." It implies a sense of agreement, estimation, or limitation. It can also suggest summarizing or condensing information.

・On-yomi (音読み): ヤク (yaku) ・Kun-yomi (訓読み): None, or rarely used.

⚫︎ 約束 (やくそく) Translation: Promise, appointment. ⚫︎ 約10分 (やくじゅっぷん) Translation: Approximately 10 minutes. ⚫︎ 予約 (よやく) Translation: Reservation.

The kanji 約 is a phono-semantic compound (形声文字, けいせいもじ). The left side is a silk radical (糸, いと, ito), and it originally depicts silk thread. The right side is a phonetic component, 勺 (しゃく, shaku), which is a unit of volume or a ladle. The original meaning relates to binding or measuring with a thread. Over time, it developed the meanings of promise and approximately, extending its usage beyond the physical action of binding.