What does M stand for?

What does M stand for? M is the Roman numeral for thousand and MM is meant to convey one thousand-thousand — or million. To take it further; one billion would be shown as $1MMM or one-thousand million.

M is the Roman numeral for thousand and MM is meant to convey one thousand-thousand — or million. To take it further; one billion would be shown as $1MMM or one-thousand million.