Encyclopedias, Almanacs, Transcripts, and Maps
- Lumière, Louis Jean and Auguste
- lumpfish
- Lungless Salamanders (Plethodontidae)
- lupus erythematosus
- lupus vulgaris
- Luria, Isaac
- Luria, Shelomoh
- Lustratio
- lux
- Lycopodophyta
- Lyell, Charles (1797–1875)
- Lyell, Sir Charles (1797 – 1875) Scottish Geologist
- lymph gland
- Lyrebirds (Menuridae)
- Ma gcig Lab sgron (Machig Labdron)
- MacArthur, Robert Helmer (1930 – 1972) Canadian Biologist and Ecologist
- macaw
- Macedonia, Former Yugoslav Republic Of
- Mackerras, Sir (Alan) Charles
- Macmillan, Sir (Maurice) Harold