I'm reading my textbook (Worlds Together Worlds Apart Volume 1: Beginnings to the Fifteenth Century) that, at some point during the Song Dynasty, citizens of China thought their culture to be superior. The book also says these citizens referred to themselves as "Han." I've looked all over Google for more information on this statement, but all I can find is about the Han Dynasty, which happened anywhere between 1,000 to 1,400 years prior to the Song Dynasty. Does this self-given name have anything to do with the Han Dynasty? I looked up the very definition of the word "Han" but all I could find was " sorrow, spite, rancor, regret, resentment or grief, among many other attempts to explain a concept that has no English equivalent. "
I'm not simply looking for answers to my homework, because this doesn't even matter to my assignment. I'm honestly just curious as to why these people gave themselves a nickname and why it stuck so well that it made it into a history textbook. These little tiny history facts are what I live for.
(Wow I have not commented in forever on this subreddit haha.)
When we think about the "Chinese" in the modern world, we don't picture Hui Chinese people praying in Mosques, nor do we picture the Yao or the Miao, who have a long history of unique cultural customs and religion, as well as languages not related to the Sinitic languages which so many Chinese people speak today.
No, we envision a Han person, or a person of the Han ethnic group. When you found the Han Dynasty with relation to the word "han," you were right that that is the origin of the Han name. Seen as a golden age of Chinese history, this was the first long lasting, centralised, imperial dynasty of China which saw the country expand to heights previously unseen and usher in an era of trade and prosperity.
China is a large country of 1.4 billion people and over 90% of its population comes from this one ethnic group, the "Han." It is often equated with China today, but it is not the only group in China: there are 56 officially recognised ethnic groups in China and many more that unofficially exist.
It's not surprising that you would equate the two though! After all, not only does it form the vast majority of the population, "China proper," and the "history of China" has often been seen as the "history of the Han." This too is not surprising. But even this is inaccurate, as the history of China cannot be viewed in a vacuum. There are of course, the two famous "official" foreign dynasties of China: the Yuan (of the Mongols) and the Qing (of the Manchuus). However, China's history has been filled with history between multiple ethnic groups, and not just the Mongols or the Manchuus. During the expansion of the Qin and Han dynasties, we saw the assimilation of the "baiyue" people of Southern China into the Han ethnic group. During the Han Dynasty, we saw warfare and sustained conflict between the "barbarians" in the Tarim Basin as well as the Xiongnu of the Eurasian Steppe. During the Northern and Southern Dynasties, "northern Barbarians" ruled much of Northern China, while during the Southern Song era itself, the north was ruled by the Jurchen led Jin dynasty. My point is that the territories that make up "modern China" have long been under the sway of other ethnic groups and China's history is not just the "history of the Han" though they do take a central role in its stories.
So to recap: Hans are often seen as the representative group of Chinese civilisation as a whole and are the usual "shorthand" for when people are referring to Chinese. However, they are far from the only group and the history of China is not just the history of the Han. For example, the most famous admiral of China, Zheng He, was a Hui Muslim!
So hopefully that gives you a bit more background about the meaning of Han. It's a very brief and broad overview. As for the definition of "Han" you found, I believe that's a reference to a Korean concept of the word and while such a word exists in Chinese, it's a different character.
I know I didn't really talk a lot (really any) about the Song dynasty in specific, and that's because the term wasn't a particular reference or only notable during the Song dynasty. Let me know if you have any other questions.
Speaking more directly to the case of Song subjects identifying as Han people- prior to the era of the Han Dynasty, the people we now call "Chinese" had split identities, identifying with a common Hua (華) or Huaxia (華夏) culture in contrast to "barbarian" outsiders, but also politically with their particular home state, i.e. Qi or Yan or Zheng. Four hundred years of political unity and cultural assimilation under the Han erased that divide, and "man of Han" (漢人) came to mean one who was both culturally Chinese and a subject of the unified Chinese empire. In terms of Chinese cultural and intellectual life, the Han era was also important for codifying the brilliant but scattered output of the Zhou period into something more like a cohesive "national" corpus, giving rise to a cosmopolitan, pan-imperial Han elite culture in place of the old regional ones. Hua and various compounds containing it never completely fell out of use though, and continued to be used right down to the modern day (where it appears in the official names of both the PRC and the ROC, for example).
"Han" identity was further sharpened over the course of the Three Kingdoms and Northern and Southern Dynasties period, when foreign tribes (referred to collectively as the Hu 胡) carved out their own kingdoms in northern China and the former Han empire was once again politically divided. In this new environment, holding tightly to Han identity was a way of rejecting the "barbarous" Hu and their influence and declaring the hope for a reunification of the Chinese empire. In practice, of course, there was a great deal of intermixing, especially between the nomadic chiefs and the Han great families of northern China, and it was this new elite of mixed Han-Hu background which ultimately did much of the work of reunifying the Chinese empire under the Sui and Tang. But this period cemented the importance of the name "Han" to describe those people who spoke Chinese and claimed the Han Dynasty as the core of their heritage.