sec·tion / ˈsekshən/ • n. 1. any of the more or less distinct parts into which something is or may be divided or from which it is made up: arrange orange sections on a platter. ∎  a relatively distinct part of a book, newspaper, statute, or other document. ∎  a measure of land, equal to one square mile. ∎  a particular district of a town.2. a distinct group within a larger body of people or things: the children's section of the library. ∎  a group of players of a family of instruments within an orchestra: the brass section. ∎  a small class of students who are part of a larger course but are taught separately: graduate students lead discussion sections for professors' lecture courses. ∎  [in names] a specified military unit: a camouflage section was added to the army. ∎  a subdivision of an army platoon. ∎  Biol. a secondary taxonomic category, esp. a subgenus.3. the cutting of a solid by or along a plane. ∎  the shape resulting from cutting a solid along a plane. ∎  a representation of the internal structure of something as if it has been cut through vertically or horizontally. ∎  Surgery a separation by cutting. ∎  Biol. a thin slice of plant or animal tissue prepared for microscopic examination.• v. [tr.] divide into sections: she began to section the grapefruit. ∎  (section something off) separate an area from a larger one: parts of the curved balcony had been sectioned off with wrought-iron grilles. ∎  Biol. cut (animal or plant tissue) into thin slices for microscopic examination. ∎  Surgery divide by cutting: it is common veterinary practice to section the nerves to the hoof of a limping horse.DERIVATIVES: sec·tioned adj. [often in comb.] a square-sectioned iron peg.

section (sek-shŏn)
1. n. (in surgery) the act of cutting (the cut or division made is also called a section).

2. n. (in imaging) a three-dimensional reconstruction of a body scan obtained by computerized tomography or magnetic resonance imaging.

3. n. (in microscopy) a thin slice of the specimen to be examined under a microscope.

4. vb. to issue an order for the compulsory admission of a patient to a psychiatric hospital for assessment and treatment under the appropriate section of the Mental Health Act 1983.

section. Surface or portion obtained by a cut made through a structure or any part of a structure to reveal its profile, and/or interior. It may therefore show the outline of a moulding, and a drawing of an imaginary vertical cut through a building will show the elevations of the walls of internal rooms, the convention being that all beyond the plane made by the intersection of the section is depicted in elevation. A plan is therefore a section, the section-plane being horizontal, and shows the floors in elevation.

section cutting; subdivision of a written or printed work or document; part cut off XVI; drawing of an object as if cut through XVII. — F. section or L. sectiō, -ōn-, f. sect-, pp. stem of secāre cut, f. IE. *sek-.