| Long-nosed Potoroo | Potorous tridactylus |
| Long-nosed Shrew Opossum | Rhyncholestes raphanurus |
| long-playing record | microsillon |
| long-range | à longue portée |
| Long-snouted seahorse | Hippocampus guttulatus |
| long-standing | ancien |
| Long-tailed Broadbill | Eurylaime psittacin |
| Long-tailed Chinchilla | Chinchilla lanigera |
| Long-tailed Cormorant | Cormoran africain |
| Long-tailed Dunnart | Souris marsupiale à longue queue |
| Long-tailed Finch | Poephila acuticauda |
| Long-tailed Ground-roller | Brachyptérolle à longue queue |
| Long-tailed jaeger | Labbe à longue queue |
| Long-tailed Pygmy Possum | Possum pygmée à longue queue |
| Long-tailed Skipper | Urbanus proteus |
| Long-tailed Skua | Labbe à longue queue |
| Long-tailed thresher shark | Alopias vulpinus |
| Long-tailed tits | Aegithalidae |
| long-term | à longue échéance |
| Long-Term Capital Management | Long Term Capital Management |
| long-term effect | effet à long terme |
| long-term experiment | expérience sur le long terme |
| Long-toed Salamander | Ambystoma macrodactylum |
| Long-toed Stint | Bécasseau à longs doigts |
| long-winded | verbeux |
| long-windedness | exubérance |
| longboat | chaloupe |
| longbow | arc anglais |
| Longchamp Racecourse | Hippodrome de Longchamp |
| Longchenpa | Longchenpa |
| Longdistance traffic | Transport interrégional |
| Longdon Upon Tern | Longdon Upon Tern |
| Longest common subsequence problem | Plus longue sous-séquence commune |
| Longest word in English | Mots les plus longs en français |
| Longest-common subsequence problem | Plus longue sous-séquence commune |
| Longeville-lès-Metz | Longeville-lès-Metz |
| longevity | longévité |
| Longford | Longford |
| Longgang District | District de Longgang |
| Longhorn cowfish | Lactoria cornuta |
| Longhorn Moth | Nemophora degeerella |
| longing | avide |
| Longinus | Pseudo-Longin |
| Longirod | Longirod |
| longitude | longitude |
| longitude east | longitude est |
| Longitude of the ascending node | Longitude du nœud ascendant |
| longitude west | longitude ouest |
| longitudinal | longitudinal |
