MIL-STD-1165 1968 Edition, March 25, 1968
GLOSSARY OF ENVIRONMENTAL TERMS (TERRESTRIAL)
Includes all amendments and changes through Cancellation Notice 1, December 5, 1995
Additional Comments: CNCL NO S/S
The terms included in this Glossary refer to environments on the land surfaces of the earth and adjacent portions of the oceans and lower atmosphere that have a direct effect on surface conditions. For terms used in describing upper atmospheric and space environments, see the Air Force Glossary of Standardized Terms and Definitions and the NASA Dictionary of Technical Terms for Aerospace Use, listed in the Appendix. Similarly, authoritative glossary for marine environments is the Glossary of Oceanographic Term issued by the U.S. Naval Oceanographic Office. The Glossary of Meteorology, is the accepted standard for terms relating to atmospheric phenomena, except for definitions that have been modified in official publications of Defense agencies, such as the Handbook of Geophysics and Space Environments.
In order to establish a consistent basis for decisions as to what terms should be included or omitted, certain criteria were established after consultation with representatives of prospective using agencies. It was decided to include the following general classes of terms in the Military Standard: (1) environmental terms that have been standardized by the Department of Defense; (2) terms used in describing any aspect of the environment having a direct effect on men or machines; (3) names of sciences concerned with significant aspects of environment; (4) units used in measuring environmental phenomena (except as noted below); (5) abbreviations of terms commonly used in measuring or describing environmental phenomena within a particular field (e.g., A, d.b.h.); (6) terms used in describing specific effects of the environment on materiel (e.g., alligatoring); and (7) names of general classes of instruments or other devices that are used in studying and measuring environmental phenomena (but not minor variants or brand names of such instruments).
There has been no attempt to make this document a comprehensive glossary of science or technology, of which there are adequate representatives already in existence (see Appendix). Rather, all terms considered were screened for relevance to environmental research or engineering, and such relevance was the first test for their inclusion. In addition, it was decided to omit the following classes of terms, for which the reader is referred either to a standard dictionary or to one of the specialized glossaries listed in the Appendix: (1) terms that are likely to be encountered only by users who are specialists in the field to which the term applies; (2) terms that are common to science in general or to a number of sciences (for example, millimeter is omitted because it is a unit of measurement common to many sciences, but angstrom is included as a unit used chiefly in radiometry; likewise, general scientific terms such as theory, atom, and energy are not included); (3) foreign terms and localisms, unless they have been adopted as a generic term in scientific usage (for example, Santa Ana is omitted although foehn wind is included); (4) physiological, psychological, and medical terms, even when they refer to a direct effect of environmental phenomena; (5) terms used in discussing the theory of a specialized field, which require lengthy explanations to be meaningful to the non-specialist; (6) military terms that pertain to materiel, organization, or operations not directly related to the environment; and (7) trade names and copyrighted words.
Many words are used in different senses in various technologies and contexts, and not all of these usages are appropriate for inclusion in this Glossary. In cases where this might cause confusion, definitions that reflect specialized usages are identified by the name of the field to which they apply. It will be understood that inclusion of a definition in this Glossary does not prejudice the use of a defined word in other senses in other contexts. For example, the definition given for sound does not preclude the use of this term in a landforms context or as an adjective meaning "free from defects".
At any one time and place there is only one environment, consisting of the sum total of external conditions affecting material, equipment, men, or other organisms. This environment comprises a large number of components or elements, some of which are natural, occurring independently of any human activities, while others are induced by the action of machines or other man-made devices. The same element may be natural in some situations and induced in others; for example, wind resulting from a pressure gradient in the atmosphere is natural, while wind resulting from the motion of a vehicle is induced.
Natural environmental factors include climatic elements such as solar radiation, rainfall, and free-air temperatures; surface types such as sand and rock; terrain features such as mountains and plains; biological entities such as individual plants and animals as well as forests and other complex assemblages of organisms; and sporadic occurrences such as lightning and earthquakes. Most of these factors can be altered or reproduced artificially, but only on a vastly smaller scale than their occurrence in nature.
On the other hand, certain environmental factors are characteristically associated with the operation of machines or other man-made devices. Examples of these induced factors include mechanical shock, exhaust fumes, acoustical and mechanical vibration, nuclear radiation, and blast effects. Environments which are associated with the operation of particular weapons, vehicles, or other kinds of equipment may be characterized by particular induced factors and are therefore termed operational environments. It is not uncommon to find an operational environment within an environmental complex that is essentially natural. Thus within an aircraft there may be a distinctive environment including induced conditions of pressure, temperature, sound, vibration, etc., while outside the conditions are largely natural. Even the environment outside the aircraft may have induced elements, however, such as smog, wind resulting from motion, radio waves, and pavement on a runway.
This Glossary includes terms commonly used in describing and studying both natural and operational environments. Because of the impossibility of drawing a sharp line between the natural and induced factors, no attempt has been made to distinguish between them or to identify them separately in the Glossary.