1. (noun)birthrate, birth rate, fertility, fertility rate, natality the ratio of live births in an area to the population of that area; expressed per 1000population per year
2. (noun)fertility, fecundity the state of being fertile; capable of producing offspring
3. (noun)richness, rankness, prolificacy, fertility the property of producing abundantly and sustaining vigorous and luxuriant growth "he praised the richness of the soil"; "weeds lovely in their rankness"