germ

noun
  1. A microorganism, especially one that causes disease. noun
    Washing your hands regularly can help prevent the spread of germs.
    The doctor explained that the illness was caused by a germ that had entered the body.
  2. A portion of an organism capable of developing into a new one or part of one; a seed or bud. noun
    The germ of the plant began to sprout after a few days of watering.
    Within the seed lies the germ that will eventually grow into a tree.
  3. An initial stage from which something may develop; a beginning. noun
    The idea was just a germ at first, but it eventually grew into a full-fledged project.
    The germ of his novel came from a story his grandmother used to tell.