名詞 html:

1. a set of tags and rules (conforming to SGML) for using them in developing hypertext documents
   同義詞：hypertext markup language, hypertext mark-up language

HTML

n.（名詞）
A markup language used to structure text and multimedia documents and to set up hypertext links between documents, used extensively on the World Wide Web.
超文本鏈接標識語言：用以建構文章及多媒體文件并建立文件與文件間的超內文連結所使用的上升語言，普遍用于萬維網

來源：
H(yper)t(ext) M(arkup) L(anguage)
H(yper)t(ext) M(arkup) L(anguage)