UnderBar
UnderBar[expr]
displays with a bar under expr.
Examples
open allclose allProperties & Relations (1)
UnderBar is effectively a special case of Underscript:
if the output is used as input, both expressions standardize to UnderBar:
Wolfram Research (2007), UnderBar, Wolfram Language function, https://reference.wolfram.com/language/ref/UnderBar.html (updated 2020).
Text
Wolfram Research (2007), UnderBar, Wolfram Language function, https://reference.wolfram.com/language/ref/UnderBar.html (updated 2020).
CMS
Wolfram Language. 2007. "UnderBar." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/UnderBar.html.
APA
Wolfram Language. (2007). UnderBar. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/UnderBar.html