千

千 is a pictographic/indicative character.

It originally represented a large number, and its form is thought to be derived from a modified form of 十 (ten) to indicate a greater magnitude. Over time, it came to specifically mean one thousand.
Semantic development: - large number; - specific number: one thousand; - figurative meaning: many; countless.

천원 (千元) — one thousand won

천년 (千年) — one thousand years; millennium

수천 (數千) — several thousand

千 is one of the most fundamental numeric characters in Chinese, Korean, and Japanese. It is frequently used both literally (exact number) and figuratively (many, numerous).
Related characters: 百 — hundred

萬 — ten thousand

十 — ten

These characters form the basic East Asian number system.

(financial) 仟, 阡

For anti-counterfeiting purposes, a variant form 仟 is sometimes used in place of 千, and this is considered a homophone variant.