• 三月さんがつ — March
• 三人さんにん — three people
• 三日みっか — the third day / three days
• 三回さんかい — three times
• 三年生さんねんせい — third-year student
• 三角さんかく — triangle
• 第三だいさん — the third (in a series)

“三” is easy to recognize and write, making it one of the first kanji children learn. It appears in daily life, from dates and age to item counts and common expressions.