m stands for measure
m can either represent mass or moles, depending on the context.
1000
Almond M&Ms
m = mass.
mass.
Metres
Can represent anything
In chemistry, the unit "m" is typically used to represent "molarity," which is a measure of the concentration of a solution.
M represents Mass
M stands for the mass.
It represents the value of the variable m.
None of these could represent anything!