Geometric \Ge`o*met"ric\, Geometrical \Ge`o*met"ric*al\, a. [L. geometricus; Gr. ?: cf. F. g['e]om['e]trique.] Pertaining to, or according to the rules or principles of, geometry; determined by geometry; as, a geometrical solution of a problem. Note: Geometric is often used, as opposed to algebraic, to include processes or solutions in which the propositions or principles of geometry are made use of rather than those of algebra. Note: Geometrical is often used in a limited or strictly technical sense, as opposed to mechanical; thus, a construction or solution is geometrical which can be made by ruler and compasses, i. e., by means of right lines and circles. Every construction or solution which requires any other curve, or such motion of a line or circle as would generate any other curve, is not geometrical, but mechanical. By another distinction, a geometrical solution is one obtained by the rules of geometry, or processes of analysis, and hence is exact; while a mechanical solution is one obtained by trial, by actual measurements, with instruments, etc., and is only approximate and empirical. Geometrical curve. Same as Algebraic curve; -- so called because their different points may be constructed by the operations of elementary geometry. Geometric lathe, an instrument for engraving bank notes, etc., with complicated patterns of interlacing lines; -- called also cycloidal engine. Geometrical pace, a measure of five feet. Geometric pen, an instrument for drawing geometric curves, in which the movements of a pen or pencil attached to a revolving arm of adjustable length may be indefinitely varied by changing the toothed wheels which give motion to the arm. Geometrical plane (Persp.), the same as Ground plane . Geometrical progression, proportion, ratio. See under Progression, Proportion and Ratio. Geometrical radius, in gearing, the radius of the pitch circle of a cogwheel. --Knight. Geometric spider (Zo["o]l.), one of many species of spiders, which spin a geometrical web. They mostly belong to Epeira and allied genera, as the garden spider. See Garden spider. Geometric square, a portable instrument in the form of a square frame for ascertaining distances and heights by measuring angles. Geometrical staircase, one in which the stairs are supported by the wall at one end only. Geometrical tracery, in architecture and decoration, tracery arranged in geometrical figures.

Ground furze (Bot.), a low slightly thorny, leguminous shrub ({Ononis arvensis) of Europe and Central Asia,; -- called also rest-harrow. Ground game, hares, rabbits, etc., as distinguished from winged game. Ground hele (Bot.), a perennial herb ({Veronica officinalis) with small blue flowers, common in Europe and America, formerly thought to have curative properties. Ground of the heavens (Astron.), the surface of any part of the celestial sphere upon which the stars may be regarded as projected. Ground+hemlock+(Bot.),+the+yew+({Taxus+baccata">Ground hemlock (Bot.), the yew ({Taxus baccata var. Canadensisi) of eastern North America, distinguished from that of Europe by its low, straggling stems. Ground hog. (Zo["o]l.) (a) The woodchuck or American marmot ({Arctomys monax). See Woodchuck. (b) The aardvark. Ground hold (Naut.), ground tackle. [Obs.] --Spenser. Ground ice, ice formed at the bottom of a body of water before it forms on the surface. Ground ivy. (Bot.) A trailing plant; alehoof. See Gill. Ground joist, a joist for a basement or ground floor; a. sleeper. Ground lark (Zo["o]l.), the European pipit. See Pipit. Ground laurel (Bot.). See Trailing arbutus, under Arbutus. Ground line (Descriptive Geom.), the line of intersection of the horizontal and vertical planes of projection. Ground liverwort (Bot.), a flowerless plant with a broad flat forking thallus and the fruit raised on peduncled and radiated receptacles ({Marchantia polymorpha). Ground mail, in Scotland, the fee paid for interment in a churchyard. Ground mass (Geol.), the fine-grained or glassy base of a rock, in which distinct crystals of its constituents are embedded. Ground parrakeet (Zo["o]l.), one of several Australian parrakeets, of the genera Callipsittacus and Geopsittacus, which live mainly upon the ground. Ground pearl (Zo["o]l.), an insect of the family Coccid[ae]+({Margarodes+formicarum">Coccid[ae] ({Margarodes formicarum), found in ants' nests in the Bahamas, and having a shelly covering. They are strung like beads, and made into necklaces by the natives. Ground pig (Zo["o]l.), a large, burrowing, African rodent ({Aulacodus Swinderianus) about two feet long, allied to the porcupines but with harsh, bristly hair, and no spines; -- called also ground rat. Ground pigeon (Zo["o]l.), one of numerous species of pigeons which live largely upon the ground, as the tooth-billed pigeon ({Didunculus strigirostris), of the Samoan Islands, and the crowned pigeon, or goura. See Goura, and Ground dove (above). Ground pine. (Bot.) (a) A blue-flowered herb of the genus Ajuga ({A. Cham[ae]pitys), formerly included in the genus Teucrium or germander, and named from its resinous smell. --Sir J. Hill. (b) A long, creeping, evergreen plant of the genus Lycopodium+({L.+clavatum">Lycopodium ({L. clavatum); -- called also club moss. (c) A tree-shaped evergreen plant about eight inches in height, of the same genus ({L. dendroideum) found in moist, dark woods in the northern part of the United States. --Gray. Ground plan (Arch.), a plan of the ground floor of any building, or of any floor, as distinguished from an elevation or perpendicular section. Ground plane, the horizontal plane of projection in perspective drawing. Ground plate. (a) (Arch.) One of the chief pieces of framing of a building; a timber laid horizontally on or near the ground to support the uprights; a ground sill or groundsel. (b) (Railroads) A bed plate for sleepers or ties; a mudsill. (c) (Teleg.) A metallic plate buried in the earth to conduct the electric current thereto. Connection to the pipes of a gas or water main is usual in cities. --Knight. Ground plot, the ground upon which any structure is erected; hence, any basis or foundation; also, a ground plan. Ground plum (Bot.), a leguminous plant ({Astragalus caryocarpus) occurring from the Saskatchewan to Texas, and having a succulent plum-shaped pod. Ground rat. (Zo["o]l.) See Ground pig (above). Ground rent, rent paid for the privilege of building on another man's land. Ground robin. (Zo["o]l.) See Chewink. Ground room, a room on the ground floor; a lower room. --Tatler. Ground sea, the West Indian name for a swell of the ocean, which occurs in calm weather and without obvious cause, breaking on the shore in heavy roaring billows; -- called also rollers, and in Jamaica, the North sea. Ground sill. See Ground plate (a) (above). Ground snake (Zo["o]l.), a small burrowing American snake ({Celuta am[oe]na). It is salmon colored, and has a blunt tail. Ground squirrel. (Zo["o]l.) (a) One of numerous species of burrowing rodents of the genera Tamias and Spermophilus, having cheek pouches. The former genus includes the Eastern striped squirrel or chipmunk and some allied Western species; the latter includes the prairie squirrel or striped gopher, the gray gopher, and many allied Western species. See Chipmunk, and Gopher. (b) Any species of the African genus Xerus, allied to Tamias. Ground story. Same as Ground floor (above). Ground substance (Anat.), the intercellular substance, or matrix, of tissues. Ground swell. (a) (Bot.) The plant groundsel. [Obs.] --Holland. (b) A broad, deep swell or undulation of the ocean, caused by a long continued gale, and felt even at a remote distance after the gale has ceased. Ground table. (Arch.) See Earth table, under Earth. Ground tackle (Naut.), the tackle necessary to secure a vessel at anchor. --Totten. Ground thrush (Zo["o]l.), one of numerous species of bright-colored Oriental birds of the family Pittid[ae]. See Pitta. Ground tier. (a) The lowest tier of water casks in a vessel's hold. --Totten. (b) The lowest line of articles of any kind stowed in a vessel's hold. (c) The lowest range of boxes in a theater. Ground timbers (Shipbuilding) the timbers which lie on the keel and are bolted to the keelson; floor timbers. --Knight. Ground tit. (Zo["o]l.) See Ground wren (below). Ground wheel, that wheel of a harvester, mowing machine, etc., which, rolling on the ground, drives the mechanism. Ground wren (Zo["o]l.), a small California bird ({Cham[ae]a fasciata) allied to the wrens and titmice. It inhabits the arid plains. Called also ground tit, and wren tit. To bite the ground, To break ground. See under Bite, Break. To come to the ground, To fall to the ground, to come to nothing; to fail; to miscarry. To gain ground. (a) To advance; to proceed forward in conflict; as, an army in battle gains ground. (b) To obtain an advantage; to have some success; as, the army gains ground on the enemy. (c) To gain credit; to become more prosperous or influential. To get, or To gather, ground, to gain ground. [R.] ``Evening mist . . . gathers ground fast.'' --Milton. There is no way for duty to prevail, and get ground of them, but by bidding higher. --South. To give ground, to recede; to yield advantage. These nine . . . began to give me ground. --Shak. To lose ground, to retire; to retreat; to withdraw from the position taken; hence, to lose advantage; to lose credit or reputation; to decline. To stand one's ground, to stand firm; to resist attack or encroachment. --Atterbury. To take the ground to touch bottom or become stranded; -- said of a ship.