Aerospace Science & Technology Dictionary

The NASA Aerospace Science and Technology (AS&T) Dictionary brings together term definitions from over 20 NASA and non-NASA sources-totaling more that 10,000 entries and over 9,000 embedded cross references. This compilation was developed to provide a convenient resource for assisting researchers, educators, students, technical writers and others in understanding and using aerospace technical terminology.

The AS&T Dictionary covers terminology in aviation and space engineering, and the natural space sciences including astronomy, astrophysics, and planetology. In addition, terminology from supporting areas of engineering, physics, chemistry, and the Earth and life sciences are also covered. In the core aerospace areas, the coverage represents both current and historical terminology from the past 70 years of aviation and space technology.

In this first edition, over half of the definitions are either from the 1998 edition of the NASA Thesaurus or the Dictionary of Technical Terms for Aerospace Use (NASA SP-7, 1965)*. All definitions contained in these two sources are included in the AS&T Dictionary. As for the other sources, many are presented in their entirety; while for others, only those terms that were considered to be within the scope of this Dictionary are included. The Sources page gives a complete list of definition sources with links to some associated web-pages.

Wherever possible, the original entry formats of the various sources have been normalized, as well as the orthographic forms of the terms themselves. Some minor format differences exist in how synonymous terms are referenced, but in all cases the meaning of the reference is clear.

In general, duplication between the various definition sources has been eliminated. However, multiple definitions for a given term were preserved when definitions (1) address different senses of the term; (2) reflect the unique perspective of a particular application or discipline; or (3) include additional information not covered by other definitions.

A Source Note appears immediately following each term. Besides indicating the original glossary or dictionary source, this information often provides a general indication of the particular sense, slant or emphasis of a definition.

On the Sources and Related Links pages and occasionally in the body of some definitions there are links to external Internet sites. The currency of all these sites was validated just prior to releasing the AS&T Dictionary, but, as can be expected, some of these sites may eventually be moved or removed from the web.

Comments on definitions and particularly suggestions for additional sources are invited. Contact the NASA Center for AeroSpace Information at help@sti.nasa.gov or call the NASA STI Help Desk at 301-621-0390.

* A note regarding NASA SP-7, the Dictionary of Technical Terms for Aerospace Use

Early on in the development of the AS&T Dictionary, it was thought that the NASA SP-7 dictionary should be included in its entirety. Although published over 30 years ago, this resource is rich in information that is still valid today. In addition, there are hundreds of entries that relate to concepts of historical significance-reflecting the terminology of the first half century of aviation and astronautics. To ensure easy identification, a Source Note indicating "NASA SP-7, 1965" will appear after each term extracted from this source. The Forward and Introduction to the original 1965 publication, written by the editor William H. Allen and the then-director of the NASA Scientific and Technical Information Division, Melvin S. Day, has been included for reference.

Special recognition must be given to Daniel R. Glover, Jr. and the other team members from the NASA Glenn Research Center who were responsible for the original conversion of NASA SP-7 to electronic form. Without their effort, inclusion of this important source in the first edition of the AS&T dictionary would not have been possible.

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