Diacritical(a.) That which separates or distinguishes -- applied to points or marks that distinguish letters of similar form, or different sounds of the same letter, as, a, /, a, /, /, etc.
Thesaurus Entries
affection, affective, appropriate, aroma, attribute, automatism, bad habit, badge, banner, birthmark, body-build, brand, cachet, cast, categorical, character, characteristics, characterizing, classificational, classificatory, compare, complexion, composition, configuration, constituents, constitution, constitutional, contrastive, crasis, creature of habit, custom, cut, defining, denominative, device, dharma, diacritical, diagnostic, diathesis, differencing, differentia, differential, differentiative, discriminating, discriminative, disposition, dispositional, distinctive, distinctive feature, distinguished, distinguishing, divisional, divisionary, earmark, emblematic, emotional, especial, ethos, exemplary, feature, fiber, figure, flavor, force of habit, frame, genius, grain, gust, habit, habit pattern, habitude, hallmark, hue, humor, humors, idiocrasy, idiocratic, idiosyncrasy, idiosyncratic, ilk, image, impress, impression, in character, index, indicant, indicator, individual, individualism, individualizing, individuating, innate, insignia, intellectual, intrinsic, keynote, kind, lineaments, makeup, mannerism, mark, marked, marking, measure, mental, mold, natural, naturalistic, nature, normal, note, odor, ordinal, particular, particularity, pattern, peculiar, peculiarity, personalizing, physique, picture, point, practice, praxis, proper, property, quality, quintessential, quirk, realistic, regular, representation, representative, sample, savor, seal, second nature, separative, shape, sigil, sign, signal, signature, single, singular, singularity, smack, somatotype, sort, special, specialty, specific, spirit, spiritual, stamp, stereotype, stereotyped behavior, streak, stripe, subdivisional, suchness, sure sign, symbolic, symptom, symptomatic, system, taint, tang, taste, taxonomic, telltale sign, temper, temperament, temperamental, tendency, tenor, token, tone, trait, trick, true to form, true to type, typal, type, typic, typical, unique, usage, use, usual, vein, virtue, way, wont