7.6.1 \csn and \ece

\csn{name} simply abbreviates \csname name \endcsname, thus saving some typing. The extra level of expansion does take some time, though, so I don't recommend it for an inner loop.

\ece{token}{name} abbreviates

     \expandafter token \csname name \endcsname

For example,

     \def\fontabbrevdef#1#2{\ece\def{@#1font}{#2}}
     \fontabbrevdef{normal}{ptmr}

defines a control sequence \@normalfont to expand to ptmr.