Open English Wordnet
Nouns
(n)prevalencethe quality of prevailing generally; being widespread“he was surprised by the prevalence of optimism about the future”
(n)prevalence(epidemiology) the ratio (for a given time period) of the number of occurrences of a disease or event to the number of units at risk in the population
(n)preponderance, prevalencea superiority in numbers or amount“a preponderance of evidence against the defendant”