| English | Spanish |
| Bolivian red-winged tinamou | tinamú rosado o guaipo (Rhynchotus rufescens maculicollis) |
| coralline red algae | alga roja coralina |
| Madagascar red owl | lechuza de Madagascar (Tyto soumagnei) |
| non-dispersive infra-red absorption analyzer | analizador no dispersivo por absorción en los infrarrojos |
| red-backed squirrel monkey | saimiri dorsirrojo (Saimiri oerstedii) |
| red bear | oso pardo mejicano (Ursus arctos isabellinus) |
| red bellied spider monkey | ateles de Panamá (Ateles geoffroyi panamensis) |
| red-billed curassow | pauji piquirrojo (Crax blumenbachii) |
| red-browed parrot | loro de mejillas azules (Amazona rhodocorytha) |
| red-capped parrot | lorito orejudo (Pionopsitta pileata) |
| red colobus | colobo de Zanzíbar (Procolobus pennantii kirkii) |
| red-crowned amazon | loro de mejillas azules (Amazona rhodocorytha) |
| red-crowned crane | grulla de Manchuria (Grus japonensis) |
| red-crowned parrot | loro de mejillas azules (Amazona rhodocorytha) |
| red flag warning | alerta roja |
| red-fronted amazon | loro de panda roja (Amazona vittata) |
| red-fronted kakariki | cacatúa de Nueva Zelanda (Cyanoramphus novaezelandiae) |
| red-fronted parakeet | cacatúa de Nueva Zelanda (Cyanoramphus novaezelandiae) |
| red-fronted parakeet, red-fronted kakariki, New Zealand parakeet | cacatúa de Nueva Zelanda (Cynamoramphus novaezelandiae) |
| red list | lista roja |
| red list The series of publications produced by the International Union for the Conservation of Nature and Natural Resources (IUCN). They provide an inventory on the threat to rare plants and animal species. Information includes status, geographical distribution, population size, habitat and breeding rate. The books also contain the conservation measures, if any, that have been taken to protect the species. There are five categories of rarity status: endangered species; vulnerable organisms, which are those unlikely to adapt to major environmental effects; rare organisms, which are those at risk because there are few of them in the world, such as plants which only grow on mountain peaks or on islands; out of danger species, which were formerly in the above categories, but have had the threat removed because of conservation actions; and indeterminate species, which are the plants and animals probably at risk, although not enough is known about them to assess their status | lista roja |
| Red List of Threatened Animals | Lista Roja de Animales Amenazados |
| Red list of wastes | Lista roja de residuos |
| red mud | lodos rojos |
| red mud | fango rojo |
| red mud from the alumina production | Lodos rojos de la producción de alúmina |
| red-nosed saki | saki de nariz blanca (Chiropotes albinasus) |
| red panda | pequeño panda (Ailurus fulgens) |
| red seaweeds | algas rojas (Rhodophyceae) |
| red siskin | jilguero rojo (Carduelis cucullata) |
| red sludge | lodos rojos |
| red-spectacled amazon | loro de cara roja (Amazona petrei, Amazona pretrei) |
| red-spectacled parrot | loro de cara roja (Amazona petrei, Amazona pretrei) |
| red spider monkey | ateles de Panamá (Ateles geoffroyi panamensis) |
| red-tailed amazon | loro brasileño (Amazona brasiliensis) |
| red tide | marea roja |
| red tide Sea water which is covered or discoloured by the sudden growth of algal bloom or by a great increase in single-celled organisms, dinoflagellates. Red tides are often fatal to many forms of marine life and, in some cases, can result in human deaths because the dinoflagellates are eaten by clams and mussels which concentrate the paralysing toxins which they produce | marea roja |
| red tide | marea venenosa |
| Tana river red colobus | colobo de tana |
| the photometric measurement of the red colouration | fotometría de la coloración roja |
