2. The process where a seed, spore, or zygote begins to sprout, to grow, or to develop; usually after it has been dormant for a time while waiting for the right growing conditions.
3. The first outward sign of growth of a reproductive body; such as, a spore or pollen grain.
The term is commonly applied to seeds, in which germination is determined by such external conditions as water availability, temperature, and light; as well as, internal biochemical status that is appropriate before germination can occur.
Seed germination may be either epigeal, in which the cotyledons appear above the ground; or hypogeal, in which the cotyledons remain below the ground.