What is abbreviation for 1 million dollars?

Answer 1

It's really a question of context and audience.

The standard Accounting abbreviation is "MM", which is short for "Milli Milli" - a thousand thousand, meaning a million.

With the introduction of both the metric system and common technology abbreviations, which are probably closely related, and with more people being familiar with either metric or technical abbreviations than accounting abbreviations, it is becoming more common to use the Greek abbreviation, "M" (Mega - million) as a numeric abbreviation instead of the Latin "MM".

If your audience are Accountants, consider using "MM", otherwise you may feel comfortable using "M".

Generally it is referred to as a 'megabuck'.