abysm, abyss, arroyo, bottom, bottom glade, bottoms, box canyon, breach, break, canyon, cavity, chap, chasm, check, chimney, chink, cleft, cleuch, clough, clove, col, coulee, couloir, crack, cranny, crevasse, crevice, cut, cwm, dale, defile, dell, dike, dingle, ditch, donga, draw, excavation, fault, fissure, flaw, flume, fracture, furrow, gap, gape, gash, gill, glen, gorge, groove, grove, gulch, gulf, gully, gutter, hole, incision, intervale, joint, kloof, leak, linn, lunar rill, moat, notch, nullah, opening, pass, passage, rent, rift, rime, rupture, scissure, seam, slit, slot, split, strath, trench, trough, vale, valley, void, wadi, wash
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.
narrowness, thinness, narrowness, closeness, exility, exiguity, line, hair's breadth, finger's breadth, strip, streak, vein, monolayer, epitaxial deposition, thinness, tenuity, emaciation, macilency, marcor, shaving, slip, thread paper, skeleton, shadow, anatomy, spindleshanks, lantern jaws, mere skin and bone, middle constriction, stricture, neck, waist, isthmus, wasp, hourglass, ridge, ghaut, ghat, pass, ravine
, narrowing, coarctation, angustation, tapering, contraction, narrow, close, slender, thin, fine, thread-like, finespun, gossamer, paper-thin, taper, slim, slight-made, scant, scanty, spare, delicate, incapacious, contracted, unexpanded &c (expand), slender as a thread, emaciated, lean, meager, gaunt, macilent, lank, lanky, weedy, skinny, scrawny slinky, starved, starveling, herring gutted, worn to a shadow, lean as a rake, thin as a lath, thin as a whipping post, thin as a wafer, hatchet-faced, lantern-jawed, attenuated, shriveled, extenuated, tabid, marcid, barebone, rawboned, monomolecular.
furrow, groove, rut, sulcus, scratch, streak, striae, crack, score, incision, slit, chamfer, fluting, corduroy road, cradle hole, channel, gutter, trench, ditch, dike, dyke, moat, fosse, trough, kennel, ravine
, tajo, thank-ye-ma'am, furrowed, ribbed, striated, sulcated, fluted, canaliculated, bisulcous, bisulcate, bisulcated, canaliferous, trisulcate, corduroy, unisulcate, costate, rimiform.