Nanometer - A unit of length equal to one one-billionth (1 x 10-9) of a meter.⏎
Pandemic - An increase in the occurrence of a particular disease over a very large region, such as a continent or the entire globe, that is greater than what is expected over a given period of time.⏎
Reservoir - An organism in which a parasite that is pathogenic for some other organism lives and reproduces without harming its host.⏎
Prion - A causative agent of infectious disease that is composed primarily of protein.⏎