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Seed germination is renewed plant embryo activity and growth. Many germination assays score completion as radicle emergence, before seedling establishment. Seed imbibition precedes that endpoint; swelling alone is insufficient.^[ref]

Water, molecular oxygen and suitable temperature support germination; light sensitivity depends on the species and seed state. Neither illumination nor one particular temperature is universally required. Seed dormancy connects germination timing to ecology by delaying seedling establishment.^[ref]

The distinction matters when comparing propagation experiments: a treatment that increases radicle emergence need not improve later seedling survival. Define the endpoint before comparing treatments, then measure the later outcome separately.

The capacity of a living seed to produce a developing plant under suitable conditions. A seed with seed dormancy can retain seed viability. In an ideal counting exercise, if $g$ of $N$ seeds complete germination, at least $g$ were living at the start. The other $N-g$ are unresolved: a failed germination assay alone cannot separate dead seeds, seed dormancy and unsuitable conditions.