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.