Germ: 1. A cell or group of cells (called a primordium) capable of developing into an organ, a part or an organism in its entirety. Eggs and sperm are germ cells.
2. A pathogenic a microorganism. A microbe capable of causing disease. The germ theory of disease held, correctly, that these minute bodies can cause disease.
3. The figurative source or wellspring. Dr. Watson told Holmes he had the germ of an idea.
Germ is a deceptively simple word that came to us from Latin germen, meaning a sprout, bud, or offshoot. In all of its meanings, the term germ retains the idea of developing into something more mature.