Triangle over a word

Question

I couldn't find an example of below symbol.

Is there a symbol or package for this triangle?

Answer 1

Package yhmath has such an accent as extensible math accent:

\documentclass{article}
\usepackage{yhmath}
\begin{document}
\[
  \widetriangle{ABH},
  \widetriangle{\mathbf{ABH}},
  \widetriangle{\textsf{ABH}},
  \widetriangle{\textsf{\bfseries ABH}}
\]
\end{document}