| Term | Definition |
| metaphor | comparison |
| metaphysics | pertaining to beyond what is natural |
| mete | to distribute in portions |
| meteoric | momentarily dazzling; swift |
| meteorology | study of weather and climate |
| meticulous | excessively careful; finicky |
| metropolis | large city |
| mettle | courage; spirit |
| miasma | pollution; poisonous environment |
| microcosm | a miniature world |
| mien | manner; bearing |
| migratory | wandering; moving from place to place |
| milieu | environment; setting |
| militant | ready and willing to fight |
| millenium | a thousand years |
| mimic | to imitate |
| minion | a devoted follower; a highly regarded person |
| minuscule | very small |
| minute | sixtieth part of an hour; very small and insignificant |
| minutiae | insignificant details; trivia |