Nomenclature is the science of classifying things and giving them some sort of name assignment. Sometimes, things are named with words that have some sort of descriptor of the organism in another language, such as Greek or Latin. Some organisms are named after their behavior, such as the animal cell having its derivations from the discovery of cells. The first cells were plant cells, then scientists saw what they thought were more plant cells, but they moved around. They called this new type of cell an "animalcule" based on the physical property of locomotion. Sometimes organisms are named by what shape their basic body pattern represents, as is the case with bacteria. Some bacteri are spiral, while others are rod-shaped; still, others are round, or spherical. Often times, scientific laws and rules are named after the people who discovered them, such as Newtons Laws of Motion, or Archimedes Principle. Other things are simply named such as a descriptive title, such as Einsteins "Theory of General Relativity".