alveolation, alveolus, antrum, aperture, armpit, arrearage, basin, bowl, breach, break, broaching, caesura, cavity, cessation, chasm, check, clearance, clearing, cleft, concave, concavity, crack, crater, crypt, cup, defalcation, defect, deficiency, deficit, depression, dip, disclosure, discontinuity, distance between, double space, em space, en space, fenestra, fissure, fistula, fold, follicle, fontanel, foramen, freeboard, funnel chest, gap, gape, gat, gulf, hair space, half space, hiatus, hole, hollow, hollow shell, inlet, interim, intermediate space, intermission, interruption, interspace, interstice, interval, jump, lack, laying open, leak, leap, leeway, letup, lull, margin, missing link, need, omission, opening, opening up, orifice, outage, outlet, passageway, pause, pit, pocket, pore, punch bowl, room, scoop, shell, shortage, single space, sink, sinus, slot, socket, space, space between, split, stoma, suspension, throwing open, time interval, trough, ullage, uncorking, unstopping, vug, want, wantage, yawn
incompleteness, deficiency, short measure, shortcoming, insufficiency, imperfection, immaturity, half measures, defect, deficit, defalcation, omission, caret, shortage, interval, break, noncompletion, missing link, missing piece, missing part, gap, hole, lacuna
, incomplete, imperfect, unfinished, uncompleted &c (complete), defective, deficient, wanting, lacking, failing, in default, in arrear, short of, hollow, meager, lame, halfand-half, perfunctory, sketchy, crude, mutilated, garbled, docked, lopped, truncated, in progress, in hand, going on, proceeding, incompletely, by halves, caetera desunt, caret.
interval, interspace, separation, break, gap, opening, hole, chasm, hiatus, caesura, interruption, interregnum, interstice, lacuna
, cleft, mesh, crevice, chink, rime, creek, cranny, crack, chap, slit, fissure, scissure, rift, flaw, breach, rent, gash, cut, leak, dike, ha-ha, gorge, defile, ravine, canon, crevasse, abyss, abysm, gulf, inlet, frith, strait, gully, pass, furrow, abra, barranca, barranco, clove, gulch, notch, yawning gulf, hiatus maxime, hiatus valde deflendus, parenthesis, void, incompleteness, period, interim (time), with an interval, far between, breachy, rimose, rimulose, at intervals, longo intervallo.
concavity, depression, dip, hollow, hollowness, indentation, intaglio, cavity, dent, dint, dimple, follicle, pit, sinus, alveolus, lacuna
, excavation, strip mine, trough, honeycomb, cup, basin, crater, punch bowl, cell, socket, valley, vale, dale, dell, dingle, combe, bottom, slade, strath, glade, grove, glen, cave, cavern, cove, grot, grotto, alcove, cul-de- sac, gully, arch, bay, excavator, sapper, miner, honeycomb (sponge), depressed, alveolate, calathiform, cup-shaped, dishing, favaginous, faveolate, favose, scyphiform, scyphose, concave, hollow, stove in, retiring, retreating, cavernous, porous, infundibul, infundibular, infundibuliform, funnel shaped, bell shaped, campaniform, capsular, vaulted, arched.