Glossary: Terms by Shigo
HEALTH is the ability - dynamic state - to resist strain.
STRAIN is an injurious, irreversible condition caused by excessive stress.
STRESS is a reversible condition caused by a drain, blockage, disruption, or shunt of energy.
ENERGY is the force that maintains vitality.
VITALITY is the dynamic ability to grow and reproduce within the limits of vigor.
VIGOR is the genetically controlled capacity - potential - to survive after injury or infection.
INFECTION is a process of energy transfer from host to pathogen.
PATHOGEN is an agent that caused disease.
DISEASE is a process that transfers energy from the host to the pathogens and results in a condition or strain to all or part of the host.
HOST is the organism that has stored energy and is interacting with a pathogen in energy transfer.
ENERGY TRANSFER must consider the three laws of thermodynamics )paraphrased here for emphasis): 1. You can never win, only break even; 2. You can only break even at absolute zero; and 3. You can never reach absolute zero.
DEATH of organisms occurs in one of three ways by mechanical disruption, dysfunction, or infection.