THESAURUS
Tier
Indian file, array, articulation, band, bank, bed, bedding, belt, buzz, category, catena, catenation, chain, chain reaction, chaining, concatenation, connection, consecution, continuum, couche, course, cycle, deck, descent, drone, echelon, endless belt, endless round, file, filiation, floor, gallery, gamut, gradation, grade, group, grouping, hum, layer, league, ledge, level, line, lineage, measures, monotone, nexus, order, overlayer, overstory, pendulum, periodicity, pigeonhole, plenum, powder train, progression, queue, range, rank, recurrence, reticulation, rotation, round, routine, row, run, scale, seam, sequence, series, shelf, single file, spectrum, stage, step, story, stratum, string, substratum, succession, superstratum, swath, thickness, thread, topsoil, train, underlayer, understory, understratum, windrow, zone
ROGET THESAURUS
Tier
Continuity
N
continuity, consecution, consecutiveness, succession, round, suite, progression, series, train chain, catenation, concatenation, scale, gradation, course, ceaselessness, constant flow, unbroken extent, procession, column, retinue, cortege, cavalcade, rank and file, line of battle, array, pedigree, genealogy, lineage, race, ancestry, descent, family, house, line, line of ancestors, strain, rank, file, line, row, range, tier, string, thread, team, suit, colonnade, continuous, continued, consecutive, progressive, gradual, serial, successive, immediate, unbroken, entire, linear, in a line, in a row, uninterrupted, unintermitting, unremitting, unrelenting (perseverence), perennial, evergreen, constant, continuously, seriatim, in a line, in succession, in turn, running, gradually, step by step, gradatim, at a stretch, in file, in column, in single file, in Indian file.
Layer
N
layer, stratum, strata, course, bed, zone, substratum, substrata, floor, flag, stage, story, tier, slab, escarpment, table, tablet, dess, flagstone, board, plank, trencher, platter, plate, lamina, lamella, sheet, foil, wafer, scale, flake, peel, coat, pellicle, membrane, film, leaf, slice, shive, cut, rasher, shaving, integument, eschar, stratification, scaliness, nest of boxes, coats of an onion, monolayer, bilayer, trilayer, lamellar, lamellated, lamelliform, layered, laminated, laminiferous, micaceous, schistose, schistous, scaly, filmy, membranous, pellicular, flaky, squamous, foliated, foliaceous, stratified, stratiform, tabular, discoid, spathic, spathose, trilamellar, graphitic.