MM is an abbreviation that may represent one million (See 1st related link below).
M typically represents one thousand, so "MM" literally conveys "a thousand thousand".
--M is the roman numeral for 1000. Roman numerals do not interpret adjacency in the same way as equations (ie multiplication). MM would simply be 2000 much as II is 2. This reasoning may or may not be the reasoning for the formation and acceptance of the abbreviation but is a fallacy.
The following site shows that a small "m" can abbreviate million:
See 2nd link below for this site
"Abbreviations - 'Standardised' Checklist
Kilogram(s) = kg or kilos
Kilometre(s) = km
Pound(s) = lb (from the Latin libra)
Miles per hour = mph
Kilometres per hour = kph
When used with figures, there is no space between the figure and the abbreviation, eg, 5mph.
GDP = gross domestic product
CAP = common agricultural policy
IOU = I owe you
LC = letter of credit
LCs = letters of credit
p5 = page 5
pp5-15 = pages 5 to 15
P D Kennedy
PO Box
kW = kilowatt
mW = one thousandth of a watt
MW = one million watts
R&D
L&S
b = byte
kb = kilobyte
Mb = megabyte
Gb = gigabyte
Eb = exabyte
C = carbon
Pb = lead
14C = carbon-14
CO4 = carbon dioxide
CFCs = chlorofluorocarbons
US$5m = 5 million US dollars
That is = ie (from the Latin id est)
For example = eg (from the Latin exempli gratia)
And so on = etc (from the Latin et cetera)
Namely, to wit = viz (from the Latin videlicet)
These are followed by a comma except when they are at the end of a sentence (which is only possible with 'etc')."
MN is not an abbreviation for millions.
200mil
parts per million = ppm
.5M
squillion
The abbreviation for million is mil.
The abbreviation used for million is MM. This abbreviation is frequently used within financial contexts. The word million itself is derived from early Italian.
MN is not an abbreviation for millions.
i million pounds
The abbreviation for 2,000,000 is "2M", where "M" represents "million".
1 million
Million, M
1.2M
200mil
parts per million = ppm
MM is an abbreviation for million.
a mill