red onion(n = noun.food) purple onion - flat mild onion having purplish tunics; used as garnish on hamburgers and salads;
is a kind of spanish onion

alizarin red, alizarine red, american red elder, american red plum, american red squirrel, bermuda onion, brick red, brown onion sauce, canadian red pine, capital of red china, cherry red, chrome red, climbing onion, congo red, dark red, deep red, eastern red cedar, egyptian onion, european red elder, flowering onion, forest red gum, giant red paintbrush, green onion, hooker's onion, in the red, indian red, japanese red army, japanese red pine, little red riding hood, multiplier onion, nodding onion, nodding wild onion, northern red oak, onion, onion bagel, onion bread, onion butter, onion dome, onion louse, onion mildew, onion plant, onion roll, onion salt, onion smut, onion stem, onion thrips, onion yellow dwarf, onion yellow-dwarf virus, orange red, oxblood red, paint the town red, pompeian red, purple onion, purplish red, red, red admiral, red alder, red alert, red algae, red amaranth, red angel's trumpet, red army faction, red ash, red baiting, red baneberry, red bat, red bay, red bearberry, red beech, red birch, red bird's eye, red blood cell, red blooded, red bone marrow, red bordeaux, red brass, red brigades, red bryony, red buckeye, red cabbage, red campion, red carpet, red cedar, red cent, red china, red clay, red clintonia, red cloud, red clover, red cole, red complexioned, red coral, red cross, red currant, red cypress pine, red dagga, red deer, red delicious, red devil, red dog, red dogwood, red drum, red dwarf, red dwarf star, red eft, red elm, red faced, red false mallow, red fire, red flag, red fox, red giant, red giant star, red ginger, red goatfish, red goosefoot, red gram, red grouse, red guard, red gum, red hand defenders, red handed, red haw, red heat, red helleborine, red herring, red hot, red indian, red ink, red jungle fowl, red juniper, red kauri, red lauan, red lauan tree, red laver, red lead, red light, red light district, red line, red maids, red man, red maple, red marrow, red meat, red morning-glory, red mulberry, red mullet, red notice, red oak, red osier, red osier dogwood, red panda, red pepper, red periwinkle, red phalarope, red pimpernel, red pine, red planet, red poll, red porgy, red raspberry, red rat snake, red region, red river, red rockfish, red salmon, red sandalwood, red sanders, red sanderswood, red saunders, red scare, red sea, red setter, red shift, red shrubby penstemon, red silk cotton, red silk-cotton tree, red silver fir, red siskin, red snapper, red sorrel, red spider, red spider mite, red sprites, red spruce, red squirrel, red sun, red tai, red tape, red tide, red trillium, red underwing, red valerian, red water, red willow, red wine, red wolf, red worm, red-skinned onion, rhode island red, river red gum, sea onion, see red, seeing red, shumard red oak, southern red cedar, southern red oak, spanish onion, spring onion, swamp red oak, top onion, tree onion, turkey red, turn red, venetian red, vidalia onion, welsh onion, western red cedar, white onion sauce, wild onion, wild red oat