Simple categories matching plain:

• item,
• bread,
• box,
• cracker,
• food,
• thing,
• ingredient,
• cookie,
• papers,
• plant,
• biscuit,
• starches,
• material,
• grain,
• fruit,
• ware,
• meat,
• fun,
• cereal,
• surface,
• object,
• vegetable,
• fare,
• bearing,
• dessert,
• bird,
• vessel,
• wood,
• paper,
• dish,
• hardware,

Members with property plain:

• bread,
• sashimi,
• metal_panel,
• tea,
• banana,
• pale_blue,
• lamb,
• toast,
• unsalted_saltine,
• jewelry_box,
• naan,
• parquet,
• unsalted_cracker,
• stucco,
• rice,
• apple,
• barley,
• oatmeal,
• floating_barge,
• saltine,
• porridge,
• potato,
• window,
• whole_oat,
• photograph,
• pear,
• chicken,
• asbestos,
• peach,
• white_meat,
• going_dancing,
• wall,
• newspaper,
• metal,
• towel,
• steel_sword,
• bacon,
• carrot,
• saucer,
• table,
• soy,
• applesauce,
• rutabaga,
• ham,
• yoghurt,
• plate,
• linen,
• butter_tub,
• baby_bib,
• canvas_bag,
• talent_show,
• orange,
• shortbread,
• label_sheet,
• postal_paper,
• plaster_wall,
• adult_shirt,
• glass,
• mirror,
• white_bread,
• wheat,
• turkey,
• wood,
• walnut,
• flour,
• borsch,
• pine,
• cheese,
• macaroni,
• photo_papers,
• infant_cereal,
• rusk,
• sandwich,
• milk_soup,
• rice_waffle,
• baby_rice,
• vegetable,
• meatloaf,
• stone,
• millet,
• matzoh,
• plain_bagel,
• grape,
• brown-rice_millet,
• turnip,
• black_coffee,
• game,
• spikemoss,
• soup,
• trillium,
• steamed_potato,
• corn_meat,
• cherry,
• crisp_rice,
• rope,
• copy_paper,
• bones,
• pale_marbles,
• corn,
• tinned_tomato,
• wholemeal_bread,
• pork,
• pillowcase,
• mushroom,
• wooden_board,
• counter_top,
• shoe_box,
• wheat_toast,
• sausage,
• blanket,
• salad,
• bowl,
• cracker,
• gingersnap,
• baked_potato,
• stew,
• copy_papers,
• roads,
• plain_donut,
• steak,
• white_paper,
• regular_hamburger,
• juicer,
• heron,
• table_top,
• pancake,
• zwieback,
• translucent_paper,
• paper,
• maple,
• milk,
• blueberry,
• ceiling,
• brass_necklace,
• water-skiing,
• graham_wafer,
• cap,
• white_wall,
• ax,
• ash,
• food_festival,
• buckwheat,
• oak,
• tissue,
• office_paper,
• chalkboard,
• common_cracker,
• cereal,
• asphalt,
• steel,
• dry_toast,
• beef,
• steamed_vegetable,
• tool,
• sunflower_heart,
• beech,
• poultry,
• plain_biscuit,
• scottish_oatcake,
• egg,
• plain_newsprint,
• crisp,
• noodle,
• banner,
• oat,
• ham_radio,
• white_rice,
• printer_paper,
• butter_shortbread,
• vanilla_wafer,
• apricot,
• egret,
• cookie_tin,
• pelican,
• water,
• copier_paper,
• veal,
• chapatti,
• butter,
• plain_chicken,
• picture,
• goulash,
• book,
• cardboard,
• matzo,
• hickory,
• scale,
• tea_cookie,
• baked_bean,
• written_thing,
• water_cracker,
• plain_rice,
• spear,
• curry,
• hold_cheese,
• vase,
• photocopy_paper,
• semolina,
• photo_box,
• metal_bearing,
• pea,
• gelatine_dessert,
• digestive_biscuit,
• oatcake,
• gruel,
• cup,
• panel,
• microscope,
• hat_box,
• milk_pudding,
• rice_flour,
• white_potato,
• fish,
• newsprint,
• berry,
• pasta,
• crispy_rice,
• mango,
• cushion_cover,
• melon,
• rice_cake,
• wooden_club,
• concrete,
• bowls,
• liver,
• clammyweed,
• cloth,
• oatmeal_biscuit,
• rubber,