- Light-sheet microscopy
- Lightheadedness
- Lightness
- Lignans
- Lignin
- Lignin peroxidase
- Lignite
- Lignoceric acid
- Ligstroside
- Ligusticum chuanxiong
- Ligustilide
- Likelihood ratio
- Likert scale
- Likert type scale
- Lilrb1
- Lilrb4
- Lily of the valley
- Lim kinase
- Lima beans
- Limb
- Limb Body Wall Complex
- Limb bud
- Limb perfusion
- Limb-girdle muscular dystrophy
- Limbal relaxing incisions
- Limbal stem cell
- Limbal stem cell deficiency
- Limbic cortex
- Limbic encephalitis
- Limbic lobe
- Limbic system
- Limen
- Limen insulae
- Limewater
- Limit of detection
- Limiting reagent
- Limonene
- Limonin
- Limonoid
- Limp
- Limulus amebocyte lysate
- Linaclotide
- Linagliptin
- Linalool
- Linalyl acetate
- Linamarase
- Lincosamides
- Lindane
- Lindley's paradox
- Line of Gennari
- Line source
- Linea alba
- Linea aspera
- Linea semilunaris
- Lineage selection
- Linear IgA bullous dermatosis
- Linear accelerator
- Linear energy transfer
- Linear epitope
- Linear gingival erythema
- Linear no threshold model
- Linear scleroderma
- Lines of Zahn
- Lineweaver-Burk plot
- Linezolid
- Lingual artery
- Lingual frenectomy
- Lingual frenulum
- Lingual gyrus
- Lingual lipase
- Lingual nerve
- Lingual papillae
- Lingual thyroid
- Lingual tonsils
- Lingual vein
- Lingual veins
- Linguistic performance
- Linguistic validation
- Liniments
- Linitis plastica
- Linkage analysis
- Linkage disequilibrium
- Linked
- Linked-read sequencing
- Linker DNA
- Linoleic acid
- Linolein
- Linolenic acid
- Linseed
- Linseed oil
- Linum usitatissimum
- Linuron
- Lip
- Lip augmentation
- Lip balm
- Lip reading
- Lipaemia retinalis
- Lipase
- Lipectomy
- Lipedema
- Lipegfilgrastim
- Lipg
- Lipid A
- Lipid II
- Lipid bilayer
- Lipid bilayers
- Lipid biosynthesis
- Lipid droplets
- Lipid emulsion
- Lipid hypothesis
- Lipid membranes
- Lipid metabolism
- Lipid microdomain
- Lipid oxidation
- Lipid peroxidation
- Lipid peroxide
- Lipid peroxides
- Lipid pneumonia
- Lipid polymorphism
- Lipid profile
- Lipid rafts
- Lipid signaling
- Lipid storage
- Lipid storage disease
- Lipid-phosphate phosphatase
- Lipid-storage diseases
- Lipidome
- Lipidomics
- Lipids
- Lipiduria
- Lipinski's rule of five
- Lipiodol
- Lipoamide
- Lipoarabinomannan
- Lipoatrophy
- Lipoblastoma
- Lipocalin
- Lipodermatosclerosis
- Lipodystrophy
- Lipoedema
- Lipofectamine
- Lipofection
- Lipofibromatosis
- Lipofuscin
- Lipogenesis
- Lipoglycopeptide
- Lipohyalinosis
- Lipohypertrophy
- Lipoic acid
- Lipoid pneumonia