nIt's a markup language used for annotating text
nIt is
concerned with logical structure
äto identify sections, titles, section headers, chapters, paragraphs,…
nIt is not
concerned with appearance
äyou say 'this is a subtitle'
not
'this is in bold, 14pt, centered'
äyou say 'this is an example'
not
'this is in verbatim, indented by 5pts, ragged right'