Large Seal script or Great Seal script is a traditional reference to Chinese writing from before the Qin dynasty, and is now popularly understood to refer narrowly to the writing of the Western and early Eastern Zhou dynasties, and more broadly to also include the oracle bone script. The term is in contrast to the name of the official script of the Qin dynasty, which is often called . However, due to the lack of precision in the term, scholars often avoid it and instead refer more specifically to the provenance of particular examples of writing.
In the Han dynasty, when clerical script became the popular form of writing and seal script was relegated to more formal usage such as on signet seals and for the titles of stelae , the people began to refer to the earlier Qin dynasty script as 'seal' script . At that time, there was still knowledge of even older, often more complex graphs which differed from the Qin seal script forms, but which resembled them in their rounded, seal-script-like style . As a result, two terms emerged to describe them: 'greater seal script' for the more complex, earlier forms, and 'small seal script' for the Qin dynasty forms.
It is only more recently that the term 'greater seal script' has been extended to refer to Western Zhou forms or even oracle bone script, of which the Han dynasty coiners of this term were unaware. The term 'large seal script' is also sometimes traditionally identified with a group of characters from a book ca 800 BCE entitled Sh? Zhoù Piān , preserved by their inclusion in the Han dynasty lexicon, the Shuowen Jiezi. Xu Shen, the author of Shuowen, included these when they differed from the structures of the Qin seal script, and labelled the examples Zhòuwén or Zhòu graphs. This name comes from the name of the book and not the name of a script. Thus, it is not correct to refer to the ca. 800 BCE Zhoū dynasty script ''as'' Zhòuwén. Similarly, the Zhòu graphs are merely examples of large seal script when that term is used in a broad sense.