| Noun | 1. | Hystricomorpha - an order of rodents including: porcupines; guinea pigs; chinchillas; etc. animal order - the order of animals order Rodentia, Rodentia - small gnawing animals: porcupines; rats; mice; squirrels; marmots; beavers; gophers; voles; hamsters; guinea pigs; agoutis family Hystricidae, Hystricidae - Old World porcupines Erethizontidae, family Erethizontidae - New World arboreal porcupines Caviidae, family Caviidae - a family of Hystricomorpha Dasyproctidae, family Dasyproctidae - agoutis and pacas Capromyidae, family Capromyidae - coypus Chinchillidae, family Chinchillidae - small bushy-tailed South American burrowing rodents Bathyergidae, family Bathyergidae - mole rats; sand rats |