The quality of being similar.

Roget 9: relation, bearing, reference, connection, concern, cognation; correlation etc. 12; analogy; similarity etc. 17; affinity, homology, alliance, homogeneity, association; approximation etc. (nearness) 197; filiation etc. (consanguinity) 11; interest; relevancy etc. 23; dependency, relationship, relative position.    comparison etc. 464; ratio, proportion.    link, tie, bond of union.    ... show more

Roget 17: similarity, resemblance, likeness, similitude, semblance; affinity, approximation, parallelism; agreement etc. 23; analogy, analogicalness^†; correspondence, homoiousia^†, parity.    connaturalness^†, connaturality^†; brotherhood, family likeness.    alliteration, rhyme, pun.    repetition etc. 104; sameness etc. (identity) 13; uniformity etc. 16; isogamy^†.    analogue; the like; match, pendant, fellow companion, pair, mate, twin, double, counterpart, brother, sister; one's second self, alter ego, chip of the old block, par nobile fratrum [Lat.], Arcades ambo^†, birds of a feather, et hoc genus omne [Lat.]; gens de meme famille [Fr.].    parallel; simile; type etc. (metaphor) 521; image etc. (representation) 554; photograph; close resemblance, striking resemblance, speaking resemblance, faithful likeness, faithful resemblance.    ... show more

Roget 27: equality, parity, coextension^†, symmetry, balance, poise; evenness, monotony, level.    equivalence; equipollence^†, equipoise, equilibrium, equiponderance^†; par, quits, a wash; not a pin to choose; distinction without a difference, six of one and half a dozen of the other; tweedle dee and tweedle dum [Lat.]; identity etc. 13; similarity etc. 17.    equalization, equation; equilibration, co-ordination, adjustment, readjustment.    drawn game, drawn battle; neck and neck race; tie, draw, standoff, dead heat.    match, peer, compeer, equal, mate, fellow, brother; equivalent.    ... show more

Roget 75: class, division, category, categorema^†, head, order, section; department, subdepartment, province, domain.    kind, sort, genus, species, variety, family, order, kingdom, race, tribe, caste, sept, clan, breed, type, subtype, kit, sect, set, subset; assortment; feather, kidney; suit; range; gender, sex, kin.    manner, description, denomination, designation, rubric, character, stamp predicament; indication, particularization, selection, specification.    similarity etc. 17.    ... show more

Roget 216: parallelism; coextension^†; equidistance^†; similarity etc. 17.   

Dutch: analogie, correspondentie, overeenkomst, overeenstemming
Polish: konwergencja, powinowactwo, analogiczność, analogia, paralelizm, bliskość, zgodność, podobieństwo, zbieżność, pobratymstwo, pokrewieństwo ... show more

A Gestalt principle of organization holding that (other things being equal) parts of a stimulus field that are similar to each other tend to be perceived as belonging together as a unit.

synonym: law of similarity.