| Subject | English | Spanish |
| environ., nat.res. | African slender-snouted crocodile | falso gavial africano (Crocodylus cataphractus) |
| life.sc., environ. | African slender-snouted crocodile, African sharp-nosed crocodile | falso gavial africano (Crocodylus cataphractus) |
| gen. | Black colored clothing can make people appear slender | La ropa de color negro puede hacer que la gente parezca delgada |
| agric. | rhododendron slender | minadora de la hoja de la azalea (Calopilia azaleella, Caloptilia azaleella, Gracilaria azaleae, Gracilaria azaleella) |
| entomol. | rhododendron slender | polilla de la azalea Gracillaria azaleella |
| entomol. | rhododendron slender | minadora de la hoja de la azalea Gracillaria azaleella |
| agric. | rhododendron slender | polilla de la azalea (Calopilia azaleella, Caloptilia azaleella, Gracilaria azaleae, Gracilaria azaleella) |
| ichtyol. | slender anchovy | anchoa chicotera Anchoa ischana |
| nat.res. | slender bamboo shark | bamboa elegante (Chiloscyllium indicum) |
| ichtyol. | slender bambooshark | bamboa elegante Chiloscyllium indicum |
| nat.res. | slender-billed curlew | zarapito fino (Numenius tenuirostris) |
| nat.res. | slender-billed gull | gaviota picofina (Larus genei) |
| life.sc., environ. | slender-billed or long-billed curlew | zarapito fino (Numenius tenuirostris) |
| earth.sc. | slender body | cuerpo alargado |
| ichtyol. | slender catshark | pejegato menudo Schroederichthys tenuis |
| transp. | slender delta | delta agudo |
| transp. | slender delta | delta afilado |
| nat.sc., agric. | slender escolar | escolar magro (Paradiplospinus gracilis) |
| nat.res. | slender false bromegrass | glyceria maxima (Brachypodium silvaticum P. Beauv.) |
| agric. | slender foxtail | alopecuro de los campos (Alopecurus myosuroides) |
| nat.sc., agric. | slender foxtail | alopecuero de los campos (Alopecurus agrestis, Alopecurus myosuroides) |
| bot. | slender foxtail | alopécuro agreste Alopecurus agrestis |
| fish.farm. | slender frostfish | cintilla (Benthodesmus tenuis) |
| nat.sc., agric. | slender fusilier | fusilero elegante (Gymnocaesio gymnoptera) |
| entomol. | slender grain mite | ácaros de almacenamiento Tyrophagus putrescentiae |
| entomol. | slender grain mite | ácaro de los granos almacenados Tyrophagus putrescentiae |
| nat.sc., agric. | slender grouper | mero elegante (Anyperodon leucogrammicus) |
| ichtyol. | slender halfbeak | agujeta larga Hyporhamphus roberti |
| life.sc., environ. | slender-horned | rhim (Gazella leptoceros) |
| ichtyol. | slender marsh clam | guacuco de marjal esbelto Polymesoda arctata |
| industr., construct., chem. | slender needle | punzón delgado |
| nat.sc., agric. | slender oat | cigüeñita (Avena barbata Brot., Avena strigosa Schreb. ssp. barbata Thell) |
| nat.sc., agric. | slender oat | avena erizada (Avena barbata Brot., Avena strigosa Schreb. ssp. barbata Thell) |
| nat.sc., agric. | slender oat | avena morisca (Avena barbata Brot., Avena strigosa Schreb. ssp. barbata Thell) |
| nat.sc., agric. | slender oat | avena barbada (Avena barbata Brot., Avena strigosa Schreb. ssp. barbata Thell) |
| ichtyol. | slender rainbow sardine | sardina arco iris grácil Dussumieria elopsoides |
| fish.farm. | slender rainbow sardine | sardina arco iris (Dussumieria acuta, Dussumieria productissima) |
| nat.sc., agric. | slender sillago | silago magro (Sillago attenuata) |
| ichtyol. | slender smooth-hound | tollo coludo elegante Gollum attenuatus |
| nat.res., fish.farm. | slender snipefish | trompetero (Macrorhamphosus scolopax) |
| agric. | slender speedwell | verónica filiforme (Veronica filiformis) |
| agric. | slender-spiked sedge | carex gracilis (Carex acuta, Carex gracilis) |
| fish.farm. | slender sunfish | pez luna alargado (Ranzania laevis, Ranzania truncata) |
| ichtyol. | slender thread herring | machuelo hebra crinudo Opisthonema bulleri |
| transp., construct. | slender transition | transición alargada |
| nat.sc., agric. | slender tuna | atún lazón (Allothunnus fallai) |
| vet.med. | slender turkey louse | piojo del pavo Goniodes stylifer |
| vet.med. | slender turkey louse | goniodes del pavo Goniodes stylifer |
| ichtyol. | slender wenchman | panchito alargado Pristipomoides freemani |
| ichtyol. | slender wenchman | panchito menudo Pristipomoides freemani |
| nat.sc., agric. | slender wenchman | panchito menudo (Pristipomoides freemani) |
| bot. | slender yellow trefoil | trébol filiforme Trifolium filiforme |