Rot is the gradual decomposition of organic objects due to the multiple factors, such as chemical changes caused by exposure to air or sunlight, structural changes due to weathering or freeze/thaw cycles, and the action of enzymes and living organisms. Bacteria, fungi, single and multicellular animals also contribute to rot by breakingg down the organic matter for food or shelter. Rot is the pathway by which the resources once bound up in iving material are recycled back into the environment. The tern is sometimes applied to the breakdown of non-organic material as well (rotten stone, or 'metal rot' as a synonym for rusting).
Figuratively, rot' can also refer to a state of breakdown or collapse, as in 'moral rot', or a state of general neglect ('he was left to rot in jail').