Synonyms and related words :
aperture, broaching, cavity, chasm, check, clearing, cleft, crack, disclosure, fenestra, fistula, fontanel, foramen, gap, gape, gat, gulf, hiatus, hole, hollow, inlet, interval, lacuna, laying open, leak, opening, opening up, outlet, passageway, pore, slot, space, split, stoma, throwing open, uncorking, unstopping, vent, yawn