WordWeb Online

1. Give extra weight to (a communication)
   "Her gesture underlined her words";
   - underscore, emphasize, emphasise [Brit]
    
2. Draw a line or lines underneath to call attention to
   - underscore

1. A line drawn underneath (especially under written matter)
   - underscore

Derived forms: underlines, underlined, underlining

See also: foreground, highlight, play up, spotlight

Type of: accent, accentuate, emphasise [Brit], emphasize, mark, punctuate, stress, stroke

Encyclopedia: Underline