1. mass number the sum of the number of neutrons and protons in an atomic nucleus
  2. misnomer an incorrect or unsuitable name
  3. Marianne Moore United States poet noted for irony and wit (1887-1872)
  4. Mach number the ratio of the speed of a moving body to the speed of sound
  5. monomer a simple compound whose molecules can join together to form polymers
  6. mariner a person who serves as a sailor
  7. Mortimer English nobleman who deposed Edward II and was executed by Edward III (1287-1330)
  8. marinara pasta sauce containing tomatoes, garlic, and herbs
  9. mourner a person who is feeling grief
  10. marine mine an explosive mine designed to destroy ships that bump into it
  11. imaginary number (mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1
  12. meronymy the semantic relation that holds between a part and the whole
  13. meronym a word that names a part of a larger whole
  14. Myanmar a mountainous republic in southeastern Asia on the Bay of Bengal
  15. Maarianhamina a town that is the chief port of the Aland islands
  16. marine museum a tank or pool or bowl filled with water for keeping live fish and underwater animals
  17. merry andrew a person who amuses others by ridiculous behavior
  18. astronomer a physicist who studies celestial bodies and the universe
  19. Mya arenaria an edible clam with thin oval-shaped shell found in coastal regions of the United States and Europe
  20. call number a mark consisting of characters written on a book