English to English
1. the quality of prevailing generally; being widespread
he was surprised by the prevalence of optimism about the future
2. (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
3. a superiority in numbers or amount
a preponderance of evidence against the defendant
4. The quality or condition of being prevalent; superior strength, force, or influence; general existence, reception, or practice; wide extension; as, the prevalence of virtue, of a fashion, or of a disease; the prevalence of a rumor.