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Definition of Focal
1. Adjective. Having or localized centrally at a focus. "Focal infection"
2. Adjective. Of or relating to a focus. "Focal length"
Definition of Focal
1. a. Belonging to,or concerning, a focus; as, a focal point.
Definition of Focal
1. Adjective. Belonging to, concerning, or located at a focus ¹
2. Adjective. (medicine) limited to a small area ¹
¹ Source: wiktionary.com
Definition of Focal
1. pertaining to a focus [adj] - See also: focus
Medical Definition of Focal
1. Limited to one specific area. (16 Dec 1997)
Lexicographical Neighbors of Focal
Literary usage of Focal
Below you will find example usage of this term as found in modern and/or classical literature:
1. Mirrors, Prisms and Lenses: A Text-book of Geometrical Optics by James Powell Cocke Southall (1918)
"The focal lengths of a thin lens are defined exactly in the same way as the ...
Thus, the primary focal length of a lens is the ratio of the height of the ..."
2. The Encyclopaedia Britannica: A Dictionary of Arts, Sciences and General (1890)
"The distance of Uie fir»t principal point from the first focal point is called
the anterior focal length, and the term posterior focal length is applied to ..."
3. Monographic Medicine by William Robie Patten Emerson, Guido Guerrini, William Brown, Wendell Christopher Phillips, John Whitridge Williams, John Appleton Swett, Hans Günther, Mario Mariotti, Hugh Grant Rowell (1916)
"Organic disease of the brain may exist, as \ve have already said, for a long time
without the appearance of such focal symptoms, especially if the so- ..."
4. Science by American Association for the Advancement of Science (1900)
"Table 3 shows the focal planes ß and /t to be pronounced. The magnification at
д is 2, with strong brown lines on a white ground which contains faint traces ..."
5. A Treatise on the Analytic Geometry of Three Dimensions by George Salmon (1882)
"The line joining any point on a focal line to the foot of the corresponding
directrix is perpendicular to that focal line. This follows as a particular case ..."
6. A Treatise on the Line Complex by Charles Minshall Jessop (1903)
"focal points, planes and surface. The ruled surface formed by rays which meet
any given ray I is still of degree m + n; for I' being any line, ..."
7. A Treatise on Light by Robert Alexander Houstoun (1915)
"Then, when the focal length is determined, the principal planes and nodal points
can be found simply by measuring off their distances from the focal planes. ..."
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