\newcommand\secref{Section~\ref}
\newcommand\tabref{Table~\ref}
\newcommand\figref{Figure~\ref}
\newcommand\appref{Appendix~\ref}

\newcommand\defref{Definition~\ref}
\newcommand\exref{Example~\ref}
\newcommand\theoryref{Theory~\ref}

\usepackage{letltxmacro}
\LetLtxMacro{\originaleqref}{\eqref}
\renewcommand{\eqref}{Eq.~\originaleqref}