definition of
M

[1] #1 M n. [meter, metre, m] the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards). wn

[2] #2 M n. [molarity, molar concentration] concentration measured by the number of moles of solute per liter of solution. wn

[3] #3 M s. [thousand, one thousand, 1000, m, k] denoting a quantity consisting of 1,000 items or units. wn

[4] #4 M n. [thousand, one thousand, 1000, K, chiliad, G, grand, thou, yard] the cardinal number that is the product of 10 and 100. wn

[5] #5 M n. [megabyte, MB] a unit of information equal to 1000 kilobytes or 10^6 (1,000,000) bytes. wn