1.  permutation(n = noun.event) replacement, substitution, switch, transposition - an event in which one thing is substituted for another; "the replacement of lost blood by a transfusion of donor blood"
is a kind of fluctuation, variation

2.  permutation(n = noun.act) - the act of changing the arrangement of a given number of elements;
is a kind of mathematical operation, mathematical process, operation
Derived form verb permute₁

3.  permutation(n = noun.act) - complete change in character or condition; "the permutations...taking place in the physical world"
is a kind of transformation, translation

4.  permutation(n = noun.act) - act of changing the lineal order of objects in a group;
is a kind of reordering
Derived form verb permute₁

1.  The act of permuting; exchange of the thing for another; mutual transference; interchange. [1913 Webster]
"The violent convulsions and permutations that have been made in property." [1913 Webster]

2.  The arrangement of any determinate number of things, as units, objects, letters, etc., in all possible orders, one after the other; -- called also alternation. Cf. Combination, n., 4. [1913 Webster]

3.  Barter; exchange. [1913 Webster]

permutation, n.
1 a an ordered arrangement or grouping of a set of numbers, items, etc. b any one of the range of possible groupings.
2 any combination or selection of a specified number of things from a larger group, esp. Brit. matches in a football pool.

Derivative:
permutational adj.

Etymology:
ME f. OF or f. L permutatio (as PERMUTE)

N  difference, variance, variation, variety, diversity, dissimilarity, disagreement, disparity, distinction, contradistinction, alteration, modification, permutation, moods and tenses, nice distinction, fine distinction, delicate distinction, subtle distinction, shade of difference, nuance, discrimination, differentia, different thing, something else, apple off another tree, another pair of shoes, horse of a different color, this that or the other, differing, different, diverse, heterogeneous, multifarious, polyglot, distinguishable, dissimilar, varied, modified, diversified, various, divers, all manner of, all kinds of, variform, daedal, other, another, not the same, unequal, unmatched, widely apart, poles apart, distinctive, characteristic, discriminative, distinguishing, incommensurable, incommensurate, differently, il y a fagots et fagots.

N  number, symbol, numeral, figure, cipher, digit, integer, counter, round number, formula, function, series, sum, difference, complement, subtrahend, product, multiplicand, multiplier, multiplicator, coefficient, multiple, dividend, divisor, factor, quotient, submultiple, fraction, rational number, surd, irrational number, transcendental number, mixed number, complex number, complex conjugate, numerator, denominator, decimal, circulating decimal, repetend, common measure, aliquot part, prime number, prime, relative prime, prime factor, prime pair, reciprocal, totient, binary number, octal number, hexadecimal number, permutation, combination, variation, election, ratio, proportion, comparison, progression, arithmetical progression, geometrical progression, harmonical progression, percentage, permilage, figurate numbers, pyramidal numbers, polygonal numbers, power, root, exponent, index, logarithm, antilogarithm, modulus, base, differential, integral, fluxion, fluent, numeral, complementary, divisible, aliquot, reciprocal, prime, relatively prime, fractional, decimal, figurate, incommensurable, proportional, exponential, logarithmic, logometric, differential, fluxional, integral, totitive, positive, negative, rational, irrational, surd, radical, real, complex, imaginary, finite, infinite, impossible, numerically, modulo.

N  change, alteration, mutation, permutation, variation, modification, modulation, inflexion, mood, qualification, innovation, metastasis, deviation, turn, evolution, revolution, diversion, break, transformation, transfiguration, metamorphosis, transmutation, deoxidization, transubstantiation, mutagenesis transanimation, transmigration, metempsychosis, avatar, alterative, conversion, revolution &c (sudden or radical change), inversion, displacement, transference, changeableness, tergiversation, changed, newfangled, changeable, transitional, modifiable, alterative, mutatis mutandis, Int, quantum mutatus!, a change came o'er the spirit of my dream, nous avons change tout cela, tempora mutantur nos et mutamur in illis, non sum qualis eram, casaque tourner, corpora lente augescent cito extinguuntur, in statu quo ante bellum, still ending and beginning still, vox audita perit littera scripta manet.

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.