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.