# How to look up a symbol?

I know what my symbol looks like, but I don't know what the command is. How do I go about finding this out?

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I think this should become a community wiki. It's being asked over and over again, for different symbols. And maybe a better title would be 'How to look up any symbol for LaTeX?' – Count Zero Sep 15 '11 at 14:51

You can look things up in the Comprehensive LaTeX symbols list. It can usually be easily accessed with texdoc symbols or texdoc symbols-a4 (in MiKTeX the latter only).

Another good option is to try Detexify, which allows you to draw the symbol and tries to recognize what you've drawn.

If you are using unicode-math, then besides using any Unicode character list, the list of all supported symbols (texdoc unimath-symbols) is very useful as it also lists which symbols are available in the various fonts.

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+1, Detexify was a lifesaver for me, many times! – Amir Rachum Jul 26 '10 at 19:36
Yup, Detexify has become the best way to do this – Joseph Wright Jul 26 '10 at 19:38
Would you mind to change the link from "this website" to "Detexify"? Nice answer though! – Nils Schmidt Jul 28 '10 at 22:59
Detexify is particularly useful if you get it on a device with a touch screen (there are Android/iPhone apps for it) -- personally, I find it rather difficult to draw with my mouse, but finger works fine :) – TJ Ellis May 31 '11 at 19:49
It's worth pointing out that the Select from the complete list! link in the results list will display the symbols list ordered by score, so it's more useful than the intimidating term complete list might suggest. – Jake Oct 21 '11 at 6:25

Theres lots of ways of doing this, but the two I've found to be most useful are these:

• Detexify Allows you to draw the symbol, and then guesses based on similar symbols. This is great for me because I don't always remember the name of the symbol, and even if I know the name, I may not have the correct name.

• AMS LaTeX Short Math Guide This short pdf gives an overview of AMS LaTeX functionality, and includes a pretty thorough list of most of the math symbols (un)commonly used in proofs and formulas.

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+1 for the magic combination of detexify and the AMS guide – Norman Gray Jul 26 '10 at 20:25
Detexify is great, but I wouldn't say that the coverage of the Short Math Guide for LaTeX is representative. – Lover of Structure Mar 13 at 5:22

The old school way is to look it up in the Comprehensive LaTeX Symbol List (warning: 4 MB PDF file).

The new hotness is to use DeTeXify which uses handwriting recognition to look the symbol up for you.

DeTeXify even comes in an iPhone/Andriod app- you can get a free version or pay for one. The only difference is that with the paid app you are making a donation to the developer- the feature set is exactly the same.

The author is planning to work on a mobile version of the website that will supplant these apps.

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I often look up the relevant topic on Wikipedia, (e.g. Set theory) and look at the source there. Wikipedia uses LaTeX for math markup as well.

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For uncommon symbols, instead of search documentation on-line or in a big PDF to find packages and commands to include in my code, I have found useful sometimes to compile the whole table of characters of a font (even in the working document) to quickly find, for example, the skull of the omding font that is \char194. Of course, you have first to know that you have a font file with that name (omding.tfm) but then is easy:

\documentclass{article}
\usepackage{fonttable}
\begin{document}
\fonttable{omding}
\font\omding=omding
\omding  \char194
\end{document}


You can also search for a skull the in Comprehensive LaTeX symbols list, or paint a skull in Detexify, or remember the easy command "\skull" (and do not forget load the skull package and enter in math mode) o try to find a \dingbat or \ding{whatever}... but when I want a skull (really never) must be that of white bones (just try the other methods if you don't know what I mean).

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There's also an iPhone app for Detexify, which I've used occasionally, for some reason ...

Links (on the US iTunes App Store): free version and supporter version (\$0.99, same functionality).

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This reference has yet to fail me; it has all the symbols typeset along with the \foo command needed to generate them. There's also this PDF, which is considerably better put-together and covers other symbols besides the base math ones

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The LaTeX wikibook Mathematics section has been very helpful for me.

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Some utilities for lookup symbols in Unicode:

• ent2latex: A Perl script to translate Unicode symbols to LaTeX commands. (However, it doesn't utilize math fonts.)

• kcharset: A KDE application to lookup Unicode. (Well, you can input some symbols in Unicode directly, or lookup the corresponding LaTeX command by ent2latex.)

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