Texts and literature in epidemiology often make use of jargon related to<unk>  without reference to their actual definition.
A number of basic concepts recur with particular frequency:
Hazard ratio, also known as the Incidence Rate Ratio
Odds ratio
Risk ratio
Relative risk, a generic term for Rate Ratio, Risk Ratio, and sometimes the Odds Ratio.
Epidemiological methods
Comparison of birth control methods
Risk factor template
Clinical prediction rule
Point prevalence
Period prevalence
Cumulative incidence
Quantitative structure-activity relationship