Webster's Revised Unabridged Dictionary · 1913

Section

Section , noun

[Latin sectio, from secare, sectum, to cut; akin to English saw a cutting instrument: compare French section. See Saw, and compare Scion, Dissect, Insect, Secant, Segment.]

1.
The act of cutting, or separation by cutting; as, the section of bodies.
2.
A part separated from something; a division; a portion; a slice.
(a)
A distinct part or portion of a book or writing; a subdivision of a chapter; the division of a law or other writing; a paragraph; an article; hence, the character §, often used to denote such a division.
It is hardly possible to give a distinct view of his several arguments in distinct sections. — Locke
(b)
A distinct part of a country or people, community, class, or the like; a part of a territory separated by geographical lines, or of a people considered as distinct.
The extreme section of one class consists of bigoted dotards, the extreme section of the other consists of shallow and reckless empirics. — Macaulay
(c)
One of the portions, of one square mile each, into which the public lands of the United States are divided; one thirty-sixth part of a township. These sections are subdivided into quarter sections for sale under the homestead and preemption laws.
3.
(Geometry) The figure made up of all the points common to a superficies and a solid which meet, or to two superficies which meet, or to two lines which meet. In the first case the section is a superficies, in the second a line, and in the third a point.
4.
(Nat. Hist.) A division of a genus; a group of species separated by some distinction from others of the same genus; -- often indicated by the sign §.
5.
(Music) A part of a musical period, composed of one or more phrases. See Phrase.
6.
The description or representation of anything as it would appear if cut through by any intersecting plane; depiction of what is beyond a plane passing through, or supposed to pass through, an object, as a building, a machine, a succession of strata; profile.

In mechanical drawing, as in these Illustrations of a cannon, a longitudinal section (a) usually represents the object as cut through its center lengthwise and vertically; a cross or transverse section (b), as cut crosswise and vertically; and a horizontal section (c), as cut through its center horizontally. Oblique sections are made at various angles. In architecture, a vertical section is a drawing showing the interior, the thickness of the walls, etc., as if made on a vertical plane passed through a building.

Collocations (4)
Angular sections (Mathematics) , a branch of analysis which treats of the relations of sines, tangents, etc., of arcs to the sines, tangents, etc., of their multiples or of their parts. [Rare]
Conic sections (Geometry) , See under Conic.
Section liner (Drawing) , an instrument to aid in drawing a series of equidistant parallel lines, -- used in representing sections.
Thin section , a section or slice, as of mineral, animal, or vegetable substance, thin enough to be transparent, and used for study under the microscope.