A technical definition is a definition in
technical communication
Technical communication is used to convey scientific, engineering, or other technical information. Individuals in a variety of contexts and with varied professional credentials engage in technical communication. Some individuals are designated as ...
describing or explaining
technical terminology
Jargon is the specialized terminology associated with a particular field or area of activity. Jargon is normally employed in a particular Context (language use), communicative context and may not be well understood outside that context. The conte ...
. Technical definitions are used to introduce the vocabulary which makes communication in a particular field succinct and unambiguous. For example, the ''iliac crest'' from medical terminology is the top ridge of the hip bone (see
ilium).
Types of technical definitions
There are three main types of technical definitions.
[Johnson-Sheehan, R: ''Technical Communication Today'', pages 507-522. Pearson Longman, 2007]
# Power definitions
# Secondary definitions
# Extended definitions
Examples
Aniline
Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine
In organic chemistry, an aromatic amine is an organic compound consisting of an aroma ...
, a benzene ring with an amine group, is a versatile chemical used in many organic syntheses.
The genus ''
Helogale
''Helogale'' is a genus of the mongoose family (Herpestidae). It consists of two species and 12 subspecies:
Extant Species
The helogales are the smallest species of mongooses and both are endemic to Africa. The distribution of the Ethiopian ...
'' (dwarf mongooses) contains two species.
Sentence definitions
These definitions generally appear in three different places: within the text, in margin notes, or in a glossary. Regardless of position in the document, most sentence definitions follow the basic form of term, category, and distinguishing features.
Examples
A
major scale
The major scale (or Ionian mode) is one of the most commonly used musical scales, especially in Western music. It is one of the diatonic scales. Like many musical scales, it is made up of seven notes: the eighth duplicates the first at double i ...
is a
diatonic scale
In music theory, a diatonic scale is any heptatonic scale that includes five whole steps (whole tones) and two half steps (semitones) in each octave, in which the two half steps are separated from each other by either two or three whole steps, ...
which has the
semitone
A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically.
It is defined as the interval between two adjacent no ...
interval pattern 2-2-1-2-2-2-1.
* term: major scale
* category: diatonic scales
* distinguishing features: semitone interval pattern 2-2-1-2-2-2-1
In mathematics, an
abelian group
In mathematics, an abelian group, also called a commutative group, is a group in which the result of applying the group operation to two group elements does not depend on the order in which they are written. That is, the group operation is commut ...
is a group which is commutative.
* term: abelian group
* category: mathematical groups
* distinguishing features: commutative
Extended definitions
When a term needs to be explained in great detail and precision, an extended definition is used. They can range in size from a few sentences to many pages. Shorter ones are usually found in the text, and lengthy definitions are placed in a glossary. Relatively complex concepts in mathematics require extended definitions in which mathematical objects are declared (e.g., let ''x'' be a real number...) and then restricted by conditions (often signaled by the phrase ''such that''). These conditions often employ the universal and/or existential
quantifiers (''for all'' (
), ''there exists'' (
)).
''Note:'' In mathematical definitions, convention dictates the use of the word ''if'' between the term to be defined and the definition; however, definitions should be interpreted as though ''
if and only if
In logic and related fields such as mathematics and philosophy, "if and only if" (shortened as "iff") is a biconditional logical connective between statements, where either both statements are true or both are false.
The connective is bicondi ...
'' were used in place of ''if''.
Examples
Definition of the limit of a single variable function:
Let be a real-valued function of a real variable and , , and be real numbers. We say that ''the'' ''limit'' ''of'' ''as'' ''approaches'' ''is'' (or, ''tends to'' ''as'' ''approaches'' ) and write if, for all , there exists such that whenever satisfies , the inequality holds.
References
Technical communication