(From the Han dynasty, 206 B.C.E to 25 C.E.) One of the set of glyphs common to Chinese (where they are called "hanzi"), Japanese (where they are called kanji), and Korean (where they are called hanja).
Han characters are generally described as "ideographic", i.e., picture-writing; but see the reference below.
Modern Korean, Chinese and Japanese fonts may represent a given Han character as somewhat different glyphs. However, in the formulation of Unicode, these differences were folded, in order to conserve the number of code positions necessary for all of CJK. This unification is referred to as "Han Unification", with the resulting character repertoire sometimes referred to as "Unihan".
Unihan reference at the Unicode Consortium.
[John DeFrancis, "The Chinese Language: Fact and Fantasy", University of Hawaii Press, 1984].