noun
character entity set
Technical computing term for a set of character entities, used in contexts such as SGML/XML document type definitions.
SGMLでは、文字実体集合を定義して特殊文字を扱う。
In SGML, a character entity set is defined to handle special characters.
Compound of 文字 (character), 実体 (entity), and 集合 (set), likely a calque from English 'character entity set'.