fertility UK /fə(ɹ)ˈtɪlɪti/US /fɝˈtɪləti/ noun3 •The condition, or the degree, of being fertile.Muckspreading increases the fertility of the soil. •The birthrate of a population; the number of live births per 1000 people per year. •The average number of births per woman within a population. formsfertilities