• 千せん — thousand
• 二千にせん — two thousand
• 千円せんえん — 1,000 yen
• 千人せんにん — a thousand people
• 千年せんねん — a thousand years
• 千葉県ちばけん — Chiba Prefecture
• 千代田区ちよだく — Chiyoda Ward (Tokyo)
• 数千すうせん — several thousand

“千” is a core number kanji meaning one thousand. You’ll see it in money (千円), time (千年), and quantity words like 数千 (several thousand). In expressions, it can also suggest “a lot,” not only an exact count.