1. the percent of seeds, spores or pollen grains in a given sample germinating within a given period (the energy period), e.g., seven, 14, or 18 days, under optimum or stated conditions 2. the percent of seeds, spores, or pollen grains in a given sample that have germinated up to the time of peak germination, generally taken as the highest number of germinations in a 24-hour period —note germinative energy is a measure of the rate of germination —see germinative capacity, seed purity, seed quality, viability This definition last updated 10/27/2008