Category Nuances matching opening:

• necessary,
• smaller,
• small,
• natural,
• operational,
• structural,
• conventional,
• horizontal,
• rectangular,
• permanent,
• architectural,
• narrow,
• exterior,
• outside,
• trim,
• underground,
• circular,
• larger,
• decorative,
• fleshy,
• symmetrical,
• size,
• vertical,
• prepared,
• off,
• fixed,
• gothic,
• surrounding,
• accessible,
• important,
• developing,
• large,
• external,
• outer,
• framed,
• adjacent,
• outdoor,
• curved,
• fine,
• typical,
• mechanical,
• epidermal,
• close,
• over,

Members for simple category opening:

• mouth,
• air-conditioner_opening,
• kiosk_windows,
• windows,
• door_windows,
• key_hole,
• nose,
• fault,
• attic_vent,
• fire-extinguisher_nozzle,
• mantle_cavity,
• anus,
• stoma,
• porch_enclosure,
• pore,
• electrical_box,
• trench_opening,
• crack,
• stylus_hole,
• vent,
• cowling_exit,
• tidal_crack,
• inspection_window,
• clark_cavern,
• stomate,
• lead,
• door_undercut,
• window,
• broken_windows,
• crawl-space_vent,
• partition,
• starship_windows,
• pore_throat,
• enclosure,
• lenticel,
• exit,
• keyhole,
• tuber_eyes,
• perforation,
• growth_crack,
• narrow_aperture,
• stress_crack,
• leaf_hydathode,
• wide_windows,
• water_inlet,
• cavern,
• micropyle,
• inspection_port,
• urinary_space,
• tree_hole,
• vertical_slot,
• pin_hole,
• optic_foramen,
• orifice,
• air_grille,
• aperture,
• bolt_hole,
• window_opening,
• rope_opening,
• roof_vent,
• disk_slot,
• cavity,
• sink_hole,
• small_windows,
• wound,
• gap,
• surface_crack,
• slot,
• spiracle,
• spiracle_opening,
• narrow_slit,
• fissure,
• service_windows,
• core_cavity,
• counter,
• cargo_port,
• hole,
• branchial_cavity,
• single_hole,
• arched_windows,
• electrical_outlet,
• genital_pore,
• gas_outburst,
• bottle_neck,
• eyes,
• vent_opening,
• cup,
• nostril,
• limestone_cavern,
• slit,
• rock_burst,
• air_intake,
• building_windows,
• hydathode,
• turbine_opening,
• basement_windows,
• jet_inlet,
• seal_hole,
• cooling_hole,
• porthole,
• pipe_drain,
• air_vent,
• solution_cavity,
• manhole,