User blog comment:Arbington/ME3 Theories/@comment-2088100-20100716002853

Mille has historically meant one thousand, so Millennium meaning a thousand years is right in line. You don't complain that a millimeter is a thousandth of a meter do you?

From wiktionary, the etymology of the word million is: From the Italian milione (million), from mille (thousand), from the Latin mille + the augmentative suffix -one.

the suffix -one basically means "large", so a million is a "large" thousand. Add this to the fact that a million is one thousand thousands, and you see why the words are similar.

I'm not sure why I posted this. Just to be argumentative I guess. But there's why it's a millennia :P