• 知人ちじん — acquaintance
• 知識ちしき — knowledge
• 知恵ちえ — wisdom
• 通知つうち — notification
• 知覚ちかく — perception
• 承知しょうち — consent / acknowledgment
• 認知にんち — recognition / cognition
• 知事ちじ — governor
• 検知器けんちき — detector

The kanji 知 combines 矢 (arrow) and 口 (mouth), originally conveying the idea of passing on information accurately — like shooting an arrow straight to a target. Over time, it came to represent “knowing” or “being aware.”

日本にほんに行いくことを知しっています。
I know that I'm going to Japan.

先生せんせいに試験しけんの日ひを知しらせました。
I informed the teacher of the exam date.