I'd like to bolden the crossed-o but
\textbf{$\oslash$}
does nothing!
I'd like to bolden the crossed-o but
\textbf{$\oslash$}
does nothing!
There are several options for obtaining bold characters in math mode. Using the bm-package with \bm is considered the best practice for that.
Implementation
\documentclass[border=3mm]{standalone}
\usepackage{amsmath}
\usepackage{bm}
\begin{document}
Options for bold $\oslash$:
$\boldsymbol{\oslash}$ vs.
{\boldmath $\oslash$} vs.
$\bm{\oslash}$
\end{document}
Output
You can use the bm package to get bold math characters. See
How can I get bold math symbols?
However, for your actual purposes, (linguistics) you should not be using the math symbol \oslash anyway, but you should just use the regular upper case Ø, in which case it can be made boldface without any extra packages.
latin1 or utf8 You need to load the inputenc package with the correct encoding specified (unless you're using XeTeX) You also need to make sure that you are loading a font that contains that the glyph (so \usepackage[T1]{fontenc} (again, unless you are using XeTeX)). If you took my other advice, you should be using XeTeX in which case your file must be encoded utf8 and things should just work.
– Alan Munn
Jul 15 '13 at 12:41
\usepackage{bm}and$\bm{\oslash}$should do. – egreg May 26 '13 at 11:02\oslashis not the same as the HTML-entityø(a.k.a. the Danish/Norwegian letter Ø), or the diameter symbol ⌀, or the empty set symbol ∅. – kahen May 26 '13 at 11:23\textbd{$\oslash$}will produce an "Undefined control sequence" error, so I guess you mean\textbf{$\oslash$}. – lockstep May 26 '13 at 12:16\oslashanyway, but rather just Ø, which you can do if you use UTF-8 as your file encoding. See the comments/answers to your other questions on this. – Alan Munn May 26 '13 at 12:23