underscore

Etymology

From under- + score.

noun

1. A line drawn or printed beneath text; the character _.
2. (music) A piece of background music.

verb

1. To underline; to mark a line beneath text.
   By convention, Rubyists usually underscore their method names. 2011, Matt Aimonetti, MacRuby: The Definitive Guide: Ruby and Cocoa on OS X, page 14
2. To emphasize or draw attention to.
   I wish to underscore the importance of proper formatting.
   The tale thus underscores in expressive form the semiparadoxical fact that traders can lie by telling the truth. 1986, Richard Bauman, Story, Performance, and Event: Contextual Studies of Oral Narrative