a colloid is

solid particles dispersed in water
a suspension where the particles settle out
a gas
I say gas, am I right?

No. http://en.wikipedia.org/wiki/Suspension_%28chemistry%29

Okay, Thank you, bobpursley,

No, you're not right. A colloid is actually a mixture where solid particles or liquid droplets are dispersed within a continuous medium, such as a liquid or a gas. So, the correct answer is that a colloid is solid particles or liquid droplets dispersed in a continuous medium, like water.