Webster
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Webster’s Revised Unabridged Dictionary · 1913

Expansion

Ex·pan′sion (·shŭn), n. [L. expansio: cf. F. expansion.] 1. The act of expanding or spreading out; the condition of being expanded; dilation; enlargement.

2. That which is expanded; expanse; extend surface; as, the expansion of a sheet or of a lake; the expansion was formed of metal.

The starred expansion of the skies. Beattie.

3. Space through which anything is expanded; also, pure space.

Lost in expansion, void and infinite. Blackmore.

4. (Com.) Enlargement or extension of business transactions; esp., increase of the circulation of bank notes.

5. (Math.) The developed result of an indicated operation; as, the expansion of (a + b)2 is a2 + 2ab + b2.

6. (Steam Engine) The operation of steam in a cylinder after its communication with the boiler has been cut off, by which it continues to exert pressure upon the moving piston.

7. (Nav. Arch.) The enlargement of the ship mathematically from a model or drawing to the full or building size, in the process of construction. Ham. Nav. Encyc.

☞ Expansion is also used adjectively, as in expansion joint, expansion gear, etc.

Expansion curve, a curve the coördinates of which show the relation between the pressure and volume of expanding gas or vapor; esp. (Steam engine), that part of an indicator diagram which shows the declining pressure of the steam as it expands in the cylinder. — Expansion gear (Steam Engine). a cut-off gear. See Illust. of Link motion. — Automatic expansion gear or cut-off, one that is regulated by the governor, and varies the supply of steam to the engine with the demand for power. — Fixed expansion gear, or Fixed cut-off, one that always operates at the same fixed point of the stroke. — Expansion joint, or Expansion coupling (Mech. & Engin.), a yielding joint or coupling for so uniting parts of a machine or structure that expansion, as by heat, is prevented from causing injurious strains; as: (a) A slide or set of rollers, at the end of bridge truss, to support it but allow end play. (b) A telescopic joint in a steam pipe, to permit one part of the pipe to slide within the other. (c) A clamp for holding a locomotive frame to the boiler while allowing lengthwise motion. — Expansion valve (Steam Engine), a cut-off valve, to shut off steam from the cylinder before the end of each stroke.

Webster’s Revised Unabridged Dictionary, Noah Porter, editor (Springfield, Mass.: G. & C. Merriam, 1913). Public domain. Text as transcribed by MICRA, Inc., from Project Gutenberg. Changed for Deep Dive Bible: Greek, which our source spelled in Latin letters, set in Greek letters; entries of one spelling merged into one article; Greek words our source left out (shown as “?”), read from the 1898 printing, from the same plates (the Library of Congress’s copy), where the place could be found with certainty. Of the others, 1,362 (a word or a single letter each) were inferred by AI from the context by the dictionary’s own rules and are marked with a wavy underline (tap or point at one to see the note); the rest, which could not be inferred with confidence, are left as “?”.