It is similar to poetry, which is elegant language.
Poets can say in very few words what it would take others pages, and pages, to say and not as well. Elegant coders can do the same with code.
A typical example is comparing a typical implementation of quicksort in C with mergesortquicksort in Haskell:
quicksort :: Ord a => [a] -> [a] quicksort [] = [] quicksort (p:xs) = (quicksort lesser) ++ [p] ++ (quicksort greater) where lesser = filter (< p) xs greater = filter (>= p) (lesser and greater can be inlined for a three line solution).