Part 371

2. (Bot.) An aquatic plant of the genus Sagittaria, esp. S. sagittifolia, -- named from the shape of the leaves.

Ar"row*head`ed, a. Shaped like the head of an arrow; cuneiform.

Arrowheaded characters, characters the elements of which consist of strokes resembling arrowheads, nailheads, or wedges; -- hence called also nail-headed, wedge-formed, cuneiform, or cuneatic characters; the oldest written characters used in the country about the Tigris and Euphrates, and subsequently in Persia, and abounding among the ruins of Persepolis, Nineveh, and Babylon. See Cuneiform.

Ar"row*root` (&?;), n. 1. (Bot.) A west Indian plant of the genus Maranta, esp. M. arundinacea, now cultivated in many hot countries. It said that the Indians used the roots to neutralize the venom in wounds made by poisoned arrows.

2. A nutritive starch obtained from the rootstocks of Maranta arundinacea, and used as food, esp. for children an invalids; also, a similar starch obtained from other plants, as various species of Maranta and Curcuma.

Ar"row*wood` (&?;), n. A shrub (Viburnum dentatum) growing in damp woods and thickets; -- so called from the long, straight, slender shoots.

Ar"row*worm`, n. (Zoöl.) A peculiar transparent worm of the genus Sagitta, living at the surface of the sea. See Sagitta.

Ar"row*y (&?;), a. 1. Consisting of arrows.

How quick they wheeled, and flying, behind them shot Sharp sleet of arrowy showers. Milton.

2. Formed or moving like, or in any respect resembling, an arrow; swift; darting; piercing. "His arrowy tongue." Cowper.

By the blue rushing of the arrowy Rhone. Byron.

With arrowy vitalities, vivacities, and ingenuities. Carlyle.

||Ar*roy"o (&?;), n.; pl. Arroyos (&?;). [Sp., fr. LL. arrogium; cf. Gr. &?; river, stream, fr. &?; to flow.] 1. A water course; a rivulet.

2. The dry bed of a small stream. [Western U. S.]

||Ar"schin (&?;), n. See Arshine.

Arse, n. [AS. ears; ærs; akin to OHG. ars. G. arsch, D. aars, Sw. ars, Dan. arts, Gr. &?; (cf. &?; tail).] The buttocks, or hind part of an animal; the posteriors; the fundament; the bottom.

Ar"se*nal, n. [Sp. & F. arsenal arsenal, dockyard, or It. arzanale, arsenale (cf. It. & darsena dock); all fr. Ar. dr&?;in'a house of industry or fabrication; dr house + &?;in art, industry.] A public establishment for the storage, or for the manufacture and storage, of arms and all military equipments, whether for land or naval service.

Ar"se*nate (&?;), n. (Chem.) A salt of arsenic acid.

Ar*se"ni*ate, n. See Arsenate. [R.]

Ar"se*nic (är"s*nk; 277), n. [L. arsenicum, Gr. 'arseniko`n, 'arreniko`n, yellow orpiment, perh. fr. 'arseniko`s or better Attic 'arreniko`s masculine, 'a`rrhn male, on account of its strength, or fr. Per. zernkh: cf. F. arsenic.] 1. (Chem.) One of the elements, a solid substance resembling a metal in its physical properties, but in its chemical relations ranking with the nonmetals. It is of a steel- gray color and brilliant luster, though usually dull from tarnish. It is very brittle, and sublimes at 356° Fahrenheit. It is sometimes found native, but usually combined with silver, cobalt, nickel, iron, antimony, or sulphur. Orpiment and realgar are two of its sulphur compounds, the first of which is the true arsenicum of the ancients. The element and its compounds are active poisons. Specific gravity from 5.7 to 5.9. Atomic weight 75. Symbol As.

2. (Com.) Arsenious oxide or arsenious anhydride; -- called also arsenious acid, white arsenic, and ratsbane.

Ar*sen"ic, a. (Chem.) Pertaining to, or derived from, arsenic; -- said of those compounds of arsenic in which this element has its highest equivalence; as, arsenic acid.

Ar*sen"ic*al, a. Of or pertaining to, or containing, arsenic; as, arsenical vapor; arsenical wall papers.

Arsenical silver, an ore of silver containing arsenic.

Ar*sen"i*cate, v. t. [imp. & p. p. Arsenicated; p. pr. & vb. n. Arsenicating.] To combine with arsenic; to treat or impregnate with arsenic.

Ar*sen"i*cism, n. (Med.) A diseased condition produced by slow poisoning with arsenic.

Ar"sen*ide (&?;), n. (Chem.) A compound of arsenic with a metal, or positive element or radical; -- formerly called arseniuret.

Ar`sen*if"er*ous (&?;), a. [Arsenic + -ferous.] Containing or producing arsenic.