Good Morning,

My question is to why the variable "m" was chosen to represent the slope of a linear equation. I always told my class to think of "m" for "m"ountain slope. But what is the real reason for this?

Thank You Kindly,

8th Grade Math Teacher

Hi John,

This is a question we have received a number of times and the short answer is that we don't know. One of our standard references on mathematical symbols is "Earliest Uses of Various Mathematical Symbols", a resource maintained by Jeff Miller, a teacher at Gulf High School in New Port Richey, Florida (The URL is If you go to his site, choose "Symbols used in geometry" and scroll down the page to "slope" you will find some historical notes that end with the paragraph

It is not known why the letter m was chosen for slope; the choice may have been arbitrary. John Conway has suggested m could stand for "modulus of slope." One high school algebra textbook says the reason for m is unknown, but remarks that it is interesting that the French word for "to climb" is monter. However, there is no evidence to make any such connection. Descartes, who was French, did not use m. In Mathematical Circles Revisited (1971) mathematics historian Howard W. Eves suggests "it just happened." Cheers,
Go to Math Central