noun

• The act of preserving, guarding, or protecting; the keeping (of a thing) in a safe or entire state; preservation.
• Wise use of natural resources.
• (biology) The discipline concerned with protection of biodiversity, the environment, and natural resources
• (biology) Genes and associated characteristics of biological organisms that are unchanged by evolution, for example similar or identical nucleic acid sequences or proteins in different species descended from a common ancestor
• (culture) The protection and care of cultural heritage, including artwork and architecture, as well as historical and archaeological artifacts
• (physics) lack of change in a measurable property of an isolated physical system (conservation of energy, mass, momentum, electric charge, subatomic particles, and fundamental symmetries)