- Mantispidae
- Manteidae
- Muscoidea
- Meloidae
- Melolonthidae
- Membracidae
- Miridae
- Mantidae
- Mastotermitidae
- Maltese cat
- mouser
- molded salad
- meetinghouse
- military science
- membranophone
- mexican freetail bat
- molasses taffy
- min dialect
- make off
- move out
- mallon
- mary mallon
- murine typhus
- mean solar time
- mean solar day
- microsecond
- msec
- mean time
- mflop
- mhz
- militate against
- malaysia militant group
- mellisonant
- Moonie
- missioner
- marsh trefoil
- marshal saxe
- Mon
- mown
- mild steel
- medium steel
- martes zibellina
- marten cat
- monosaccharose
- maple sugar
- munja
- marquis de sade
- masochist
- misery
- martyr operation