This definition sounds like a fantasy story!

"The phylum of the kingdom Protista that includes unicellular, animal like microorganisms. Many protozoa are saprophytes that live on dead matter in water and in soil. Many parasitic protozoa infect only humans without adequate immunological defenses..."

Tee hee :) Sometimes my medical dictionary is fun! I still need a simpler answer to what a protozoa is. It also told me that it's the plural of protozoon and when I looked that up, it said pertaining to protozoa. Unicellular organism. Yep I figured that much :)