pair

[procedure] pair xs

[procedure] tuples xs n

Groups every two elements (pair) or n elements (tuples) in xs.

arc> (pair '(a b c d e f))
((a b) (c d) (e f))
arc> (pair '(a b c d e))
((a b) (c d) (e))
arc> (tuples '(a b c d e) 3)
((a b c) (d e))

Gauche has similar stuff: scheme:slices.