- monotremates (fossil)
- monotremes
- monotropic liquid crystal
- monotropism
- monotropy
- monotype
- monotype theorem
- monotypic convex surface
- monotypic genus
- monotypic species
- mono-unary
- mono-unary algebra
- monovalent
- monovalent vaccine forveterinary use
- monovariant
- monozygotic twins
- Monroe Beardsley
- Monroe Doctrine
- Monrovia
- Monrovia Group
- mons
- Mons Ampère
- Mons Argaeus
- Mons Claudianus Quarry
- MONSEE