I need a way of encoding the geometry line symbol. $\overline{AB}$ gives me the line segment symbol and $\overrightarrow{AB}$ gives me the ray symbol, I need a way to get a bar over the letters that has arrows on both ends. $\overrightleftarrow{AB}$ does not work.


  • You can use tex.stackexchange.com/q/14/17423 with \overset to produce what you want. Something like \newcommand\Line[1]{\overset{\leftrightarrow}{#1}}, perhaps (untested) (By the way.... Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format.( – Sean Allred Sep 26 '14 at 16:56
  • 2
    take a look at Partial derivative with rightleftarrow on top of it. (if it is what you want, this question is a duplicate.) – barbara beeton Sep 26 '14 at 17:01
  • Freakin' called it. :) Though, looking at the output, such lines are usually longer in geometry (at least with the professor I studied under). There's definitely a question about lengthening that line, though I can't put my finger on it. A combination of that link and the question I'm thinking of would cover this Q. – Sean Allred Sep 26 '14 at 17:08
  • Almost found something that works: \newcommand{\Line[1]}{\xleftrightarrow[\displaystyle{#1}]{}} The problem is that the line is justified with the text, not the letters. Both the suggestions with \overset don't make the line long enough. – GeometryTeacher Sep 26 '14 at 18:00

Use $\overleftrightarrow{AB}$ with the mathtools or amsmath packages.


You can use


from the the MnSymbol package.

  • Not the traditional line segment symbol – Nathan Oct 9 '20 at 17:05

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