(1) Having the left side of the brain dominant.
(2) Of or relating to an individual having a consistent preference for use of the left side of the brain, hence, is usually associated with having a behavior dominated by logic, analytical thinking and verbal communication.
The human brain is separated by a longitudinal fissure creating two distinct cerebral hemispheres. The two sides of the brain resemble each other yet their functions are lateralized. Analytical, logical, and verbal functions, as well as skills for exact calculation and literal language are localized in the left hemisphere. Holistic, prosodic and intuitive functions, including skills for approximate calculations and contextual language are localized in the right hemisphere.
A left-brained person is described to be more inclined at using the left side of his brain, as such, he is also described to be more analytical, logical and verbal rather than being creative, emotional and intutive.
However, lateralizations are not applicable in every case, and there is no such a person who is “left-brained only” or “right-brained only”.
See also: laterality, lateralization.