[crystalk]

Roman numeral M = 1000.

I know of no culture or place where the use of M would imply a million.

[SauronOfMordor]

I know of no culture or place where the use of M would imply a million.

In the US, particularly among people who use computers, "M" is used for million (mega) and K is used for thousand (kilo)

[donmeaker]

Engineers routinely use M for Mega..... G for Giga, K for Kilo. You have heard of Kilometers? It is part of the international system of measurement, or SI.

Mega is a million of what ever it is