Webster
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Webster’s Revised Unabridged Dictionary · 1913

Valve

Valve (vălv), n. [L. valva the leaf, fold, or valve of a door: cf. F. valve.]

1. A door; especially, one of a pair of folding doors, or one of the leaves of such a door.

Swift through the valves the visionary fair Repassed. Pope.

Heavily closed, . . . the valves of the barn doors. Longfellow.

2. A lid, plug, or cover, applied to an aperture so that by its movement, as by swinging, lifting and falling, sliding, turning, or the like, it will open or close the aperture to permit or prevent passage, as of a fluid.

☞ A valve may act automatically so as to be opened by the effort of a fluid to pass in one direction, and closed by the effort to pass in the other direction, as a clack valve; or it may be opened or closed by hand or by mechanism, as a screw valve, or a slide valve.

3. (Anat.) One or more membranous partitions, flaps, or folds, which permit the passage of the contents of a vessel or cavity in one direction, but stop or retard the flow in the opposite direction; as, the ileocolic, mitral, and semilunar valves.

4. (Bot.) (a) One of the pieces into which a capsule naturally separates when it bursts. (b) One of the two similar portions of the shell of a diatom. (c) A small portion of certain anthers, which opens like a trapdoor to allow the pollen to escape, as in the barberry.

5. (Zoöl.) One of the pieces or divisions of bivalve or multivalve shells.

Air valve, Ball valve, Check valve, etc. See under Air. Ball, Check, etc. — Double-beat valve, a kind of balance valve usually consisting of a movable, open-ended, turban-shaped shell provided with two faces of nearly equal diameters, one above another, which rest upon two corresponding seats when the valve is closed. — Equilibrium valve. (a) A balance valve. See under Balance. (b) A valve for permitting air, steam, water, etc., to pass into or out of a chamber so as to establish or maintain equal pressure within and without. — Valve chest (Mach.), a chamber in which a valve works; especially (Steam Engine), the steam chest; — called in England valve box, and valve casing. See Steam chest, under Steam. — Valve face (Mach.), that part of the surface of a valve which comes in contact with the valve seat. — Valve gear, or Valve motion (Steam Engine), the system of parts by which motion is given to the valve or valves for the distribution of steam in the cylinder. For an illustration of one form of valve gear, see Link motion. — Valve seat. (Mach.) (a) The fixed surface on which a valve rests or against which it presses. (b) A part or piece on which such a surface is formed. — Valve stem (Mach.), a rod attached to a valve, for moving it. — Valve yoke (Mach.), a strap embracing a slide valve and connecting it to the valve stem.

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 “?”.