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

Type of: markup language

Encyclopedia: HTML

• underreckoning
• underrun
• undersaturated
• underscore
• undersea
• underseal
• undersealed
• undersecretary
• undersell
• underseller
• undersexed
• undershirt
• undershoot
• undershorts
• undershot
• undershrub
• underside
• undersign
• undersize
• undersized
• underskirt
• underslung
• undersoil
• underspend
• understaffed