Is there a Latex symbol that looks like a sector ⌔ of a circle?

This is an implementation using pict2e; the angle is 40 degrees.

\documentclass{article}
\usepackage{pict2e}

\makeatletter
\DeclareRobustCommand{\sector}{\mathord{\mathpalette\make@sector\relax}}
\newcommand{\make@sector}[2]{%
  \settoheight{\unitlength}{$#1x$}%
  \begin{picture}(1,1.06)
  \linethickness{.08\unitlength}
  \moveto(0.5,0)
  \lineto(0.842,1)
  \curveto(.6,1.08)(.4,1.08)(0.158,1)
  \closepath
  \strokepath
  \end{picture}%
}
\makeatother

\begin{document}

$A\sector x$

$A_{x\sector}$

\end{document}

\usepackage{MnSymbol}

I just searched The Comprehensive LaTeX Symbol List and found it.

There is a symbol from the fdsymbol package called \sector.

Also, depending on your level of desperation, you might want to look through The Comprehensive LATEX Symbol List.