汉 hàn is a water character: 氵 (the three-dot water radical) + a phonetic. The water element 氵 on the left tells you the original sense is a body of water, and the right side supplies the sound. In the full traditional form 漢 the right side is the phonetic difficult-to-read element that the simplification of the 1950s replaced with the plain stroke cluster 又 (yòu, hand), giving the modern 汉. Both forms share the same reading and the same first meaning.

That first meaning is a place: the Han River, 汉水 Hànshuǐ (also 汉江 Hànjiāng), a major tributary of the Yangtze in central China. The name then climbs from the river to nearly everything Chinese:

1. The river itself. 汉水 Hànshuǐ, the watercourse the character was coined to name. The Milky Way was also called 天汉 tiānhàn (the Sky River) and 银汉 yínhàn (the Silver River) by classical poets.
2. The dynasty. The first ruler founded his realm in the Han River basin and took 汉 as its name. The Han dynasty (206 BCE to 220 CE) became the long golden age against which later China measured itself.
3. The people and their language. Because the dynasty defined the culture, the majority ethnicity came to call itself 汉族 Hànzú (the Han), its speech 汉语 Hànyǔ (Chinese), and its writing 汉字 Hànzì (Chinese characters).
4. A man, a fellow. By a later colloquial extension 汉 came to mean an adult male: 男子汉 nánzǐhàn (a real man), 好汉 hǎohàn (a brave fellow), 大汉 dàhàn (a big strapping man).

The whole chain runs from water outward: a river named a dynasty, the dynasty named a people, the people named their tongue and their script, and along the way 汉 picked up the everyday sense of a sturdy man. To write Chinese in Chinese is, literally, to write 汉字, the characters of the Han.

The leap from a place name to an ethnic name runs through one dynasty. The founder built his state in the Han River valley and named it 汉, and over its long span (206 BCE to 220 CE) the Han dynasty set the template for what Chinese civilization would be: a unified empire, a Confucian bureaucracy, a shared script, the Silk Road trade. By the time it ended, the people of that empire had begun to call themselves 汉人 Hànrén, the people of Han, and the modern ethnonym 汉族 Hànzú carries the dynasty forward to this day.

This is why 汉 sits at the center of how China names itself from the inside. The country is 中国 Zhōngguó, but the majority people are 汉族, their language 汉语, their writing 汉字. The dynasty is long gone, yet its name became the everyday word for being Chinese in the cultural and ethnic sense, a rare case of a ruling house outliving itself inside the language.

Alongside the grand senses, 汉 carries a humbler, very colloquial one: a man, a fellow, especially a sturdy or manly one. This is the 汉 of 男子汉 nánzǐhàn, a real man in the sense of someone with grit and backbone, and of 好汉 hǎohàn, a brave fellow or stout-hearted hero. The classic novel 水浒传 (Outlaws of the Marsh) is full of 好汉, the rough but loyal heroes of the marsh.

The flavor is masculine and slightly heroic or earthy. A 大汉 dàhàn is a big strapping man; a 醉汉 zuìhàn is a drunkard; a 单身汉 dānshēnhàn is a bachelor. In every case 汉 frames its man as a physical, plain-spoken type rather than a refined gentleman, which is the work the honorific 子 does in 君子. Two characters for a man, two very different registers.

Start at the water radical 氵 on the left and picture a real river, the Han, winding through central China. A king founds his realm on its banks and names the dynasty after the water (汉朝). The dynasty grows so great that its name sticks to the people (汉族), their speech (汉语), and their writing (汉字). Trace the line and you have the whole character: water, dynasty, people, language.

Then remember the side door. In everyday talk 汉 also just means a man, the sturdy plain-spoken kind: the brave 好汉 of the old novels, the bachelor 单身汉, the 男子汉 who keeps his word. When you meet 汉, ask whether it is naming the Chinese world or naming a fellow, and the water on the left will remind you where the word began.