Hi Gianmaria,
Would this do?
\version "2.19.83"
extremelyLongNameFunction =
#(define-music-function (music) (ly:music?)
(let ((varOne #{ a b b a #}))
#{
$varOne $music $varOne
#}))
#(define anAlias extremelyLongNameFunction)
\anAlias { c c c c }
That's just Scheme coding, not special in lilypond.
Andrew