ABROACH. On tap, in use; spoken of barrels of beer or other liquors. ABROAD. Synonymous with foreign, or being on a foreign station. Also an old word for _spread_; as, all sail _abroad_. ABRUPT. A word applied to steep, broken, or craggy cliffs and headlands, especially such as are bold-to and precipitous. ABSCISS. A part either of the diameter or the transverse axis of a conic section, intercepted between the vertex or any other fixed point and a semi-ordinate.--_Abscission of a planet_, its being outstripped by another, which joins a third one before it. ABSENCE. A permission occasionally obtained, on urgent affairs, by officers to quit their duties. ABSOLUTE. Anything free from conditions.--_Absolute equations_, the sum of the optic and eccentric equation, or the anomalies arising from a planet's not being equally distant from the earth at all times, and its motion not being uniform.--_Absolute gravity_ is the whole force with which a body tends downwards. ABSORPTION. A term formerly used for the sinking of islands and tracts of land, instead of _subsidence_. ABSQUATULATE. _See_ SQUATTER. ABSTRACT. A brief register of the warrant officer's stores, by which the supplies, expenses, and remains are duly balanced. An _abstract log_ contains the most important subjects of a ship's log. ABSTRACT MATHEMATICS, OR PURE. The branch which investigates and demonstrates the properties of magnitude, figure, or quantity, absolutely and generally considered, without restriction to any species in particular; such as arithmetic and geometry. A-BURTON. The situation of casks when they are stowed in the hold athwart ship, or in a line with the beam. ABUT. When two timbers or planks are united endways, they are said to _butt_ or _abut_ against each other. (_See_ BUTT.) ABYME. Places supposed to be the site of constant whirlpools, such as Charybdis, the Maelstrom, and others. It means generally an abyss. ABYSS. A deep mass of waters; in hydrography it was synonymous with _gulf_. ACADEMITE. An old term for an officer brought up at the Royal Navy Academy at Portsmouth, afterwards named the Royal Naval College. ACAIR-PHUILL. Compounded of the British _acair_ or anchor, and _phuill_, a pill, or harbour, and means a safe anchorage. ACALEPHÆ. A class of marine animals of low organization, having a translucent jelly-like structure, and frequently possessing the property of stinging, whence their name (ἀκαλήφη, a nettle). The common jelly-fish (_Medusa_) and the Portuguese man-of-war (_Physalia_) are the best-known examples. ACAST. The old word for _lost_ or _cast-away_. In weighing anchor the head-yards are generally braced _acast_, to cause the vessel to cast in the direction. "Does she take _acast_?" is frequently the question of the officer abaft. ACATER. An old word for purveyor of victuals, whence _caterer_, or superintendent and provider of a mess. Thus in Ben Jonson's "The Devil is an Ass"--