What is "hytime"

HyTime (Hypermedia/Time-based Structuring Language) is a markup language that is an application of SGML. HyTime defines a set of hypertext-oriented element types that, in effect, supplement SGML and allow SGML document authors to build hypertext and multimedia presentations in a standardized way.

HyTime is an international standard published by the ISO and IEC. The first edition was published in 1992, and the second edition was published in 1997.