1.  alteration(n = noun.event) change, modification - an event that occurs when something passes from one state or phase to another; "the change was intended to increase sales"; "this storm is certainly a change for the worse"; "the neighborhood had undergone few modifications since his last visit years ago"
is a kind of happening, natural event, occurrence, occurrent
has particulars: acceleration, deceleration, retardation, slowing, avulsion, break, mutation, sublimation, surprise, birth, nascence, nascency, nativity, breakup, detachment, separation, vagary, fluctuation, variation, conversion, death, decease, expiry, decrease, drop-off, lessening, destabilization, increase, easing, moderation, relief, deformation, transition, shift, transformation, transmutation, scintillation, sparkling, twinkle, play, shimmer, transmutation, damage, harm, impairment, development, revolution, chromosomal mutation, genetic mutation, mutation, sex change, loss of consciousness
Derived form verb alter₁

2.  alteration(n = noun.act) adjustment, modification - the act of making something different (as e.g. the size of a garment);
is a kind of change
has particulars: laxation, loosening, tightening, accommodation, adaptation, tune
Derived forms verb alter₁, verb alter₃

3.  alteration(n = noun.act) revision - the act of revising or altering (involving reconsideration and modification); "it would require a drastic revision of his opinion"
is a kind of transformation, translation
has particulars: distraction, misdirection, modulation, qualification, reorganization, metamorphosis, transfiguration

1.  The act of altering or making different. [1913 Webster]
"Alteration, though it be from worse to better, hath in it incoveniences." [1913 Webster]

2.  The state of being altered; a change made in the form or nature of a thing; changed condition. [1913 Webster]
"Ere long might perceive
Strange alteration in me." [1913 Webster]
"Appius Claudius admitted to the senate the sons of those who had been slaves; by which, and succeeding alterations, that council degenerated into a most corrupt." [1913 Webster]

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  variation, alteration, modification, moods and tenses, discrepance, discrepancy, divergency, deviation, aberration, innovation, varied, modified, diversified.

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.