ROGET THESAURUS
combinatorial
Interchange
N
interchange, exchange, commutation, permutation, intermutation, reciprocation, transposition, rearrangement, shuffling, alternation, reciprocity, castling (at chess), hocus-pocus, interchangeableness, interchangeability, recombination, combination, barter, tit for tat, cross fire, battledore and shuttlecock, quid pro quo, interchanged, reciprocal, mutual, commutative, interchangeable, intercurrent,
combinatorial, recombinant, in exchange, vice versa, mutatis mutandis, backwards and forwards, by turns, turn and turn about, each in his turn, everyone in his turn.