AR´ENDAL a seaport of Southern Norway, exporting timber, wood pulp, and iron, and owning numerous ships. It is a well-built place, having been rebuilt since the great fire of 1868. Wood pulp, paper, and cotton are manufactured. Pop. 11,000.
ARENENBERG CASTLE (mediæval, NARRENBERG), a castle and estate in the Swiss Canton Thurgau, the possession of Queen Hortense, who died there in 1837. In 1855 it became the property of the Empress Eugénie.
ARENGA, a term sometimes used as the generic name of the areng or gomuti palm, which is then botanically designated _Arenga saccharifera_. See _Gomuti_.
ARE´OLAR TISSUE, an assemblage of fibres in bundles, pervading almost every part of the animal structure, and connected with each other so as to form innumerable small cavities, the whole serving as a means by which the various organs and parts of organs are connected together. It is called also _Cellular Tissue_ and _Connective Tissue_. The fibres are of two kinds--white fibrous tissue and yellow elastic fibrous tissue, and interspersed among the bundles or occupying the cellular cavities are cells and corpuscles of several kinds. It is a tissue found in large quantities under the skin, covering the muscles, the blood-vessels, and nerves, and in various parts forming a kind of protective covering for delicate and important organs. It is because of its general distribution, and because of its binding various structures together, that it is called _connective_.--In botany the term is sometimes applied to the _non_-vascular substance, composed entirely of untransformed cells, which forms the soft substance of plants.
AREOM´ETER (from Gr. _araios_, thin, _metron_, a measure), an instrument for measuring the specific gravity of liquids; a _hydrometer_ (q.v.).
AREOP´AGUS, the oldest of the Athenian courts of justice, an assembly having a position more august than an ordinary court, and in its best days exercising a general supervision over public morals. It obtained its name from its place of meeting, on the Hill of Ares (Mars), near the Acropolis or citadel of Athens. Another explanation connects the word with _Aræ_ (Curses), commonly known as _Semnæ_ (Awful Goddesses), who were the guardians of the hill. It existed from very remote times, and the crimes tried before it were wilful murder, poisoning, robbery, and arson, while it had under its control also dissoluteness of morals, and innovations in the State and in religion. Its meetings were held in the open air, and its members were selected from those who had held the office of archon. The tribunal eventually lost many of its powers, but it continued to exist in name at least as late as the time of Cicero or later, having had an existence of seven or eight hundred years.