A data structure which represents every style defined within the Word document. The STSH records a unique name string for every style and associates each name with a particular CHP and/or a PAP. The indexes used to refer to individual styles are called ISTDs (Indexes to STyle Descriptors). Every PAPX for every paragraph recorded in a document contains an ISTD which identifies the style from which a paragraph inherited its default character and paragraph properties. CHPXs recorded for the text within the paragraph and PAPXs recorded for the paragraph itself encode changes that the user has made with respect to the style's default properties.