Symbol (Gr. symbolon, ‘a sign’) is sometimes used of arbitrary or other conventional marks (as of letters of the alphabet, numbers, &c.) which greatly abbreviate methods of scientific expression, as in algebra and mathematics, and especially in chemistry (for chemical symbols, see CHEMISTRY, ATOMIC THEORY). Alchemy and Astrology (q.v.) raised a large crop of symbols; from the latter astronomy has derived not a few. But symbol is now usually almost synonymous with emblem—a concrete and visible figure standing for something moral, intellectual, or religious. A lion is the symbol of courage, a lamb of meekness, &c. Greek and Roman mythology produced a large number of symbols—the trident of Neptune, the peacock of Juno, &c. Early Christian symbolism—originating mainly in a Greek colony in Rome—may be traced in the Catacombs, and an outline of its development has been already sketched in the article CATACOMBS. The greatest number of symbols are those which represent Christ—some mere letters or combinations of letters, as the Monogram (q.v.), composed of A and Ω, of IX and Ϡ (for Christos; see CROSS), of ΙΗΣ (initials of Iesous). Of another kind is the word ΙΧΘΥΣ, the Greek word for fish, the several letters standing for the initial letters of the Greek words Ἰησοῦς Χριστὸς Θεοῦ Υἱὸς Σωτήρ. The symbol of a pictured fish is also used for Christ; and some contend that this symbol, for whatever reason, was in use before the acrostic word was invented or thought of. Then there are pictures of the Good Shepherd, the True Vine, &c. (see also SAINT). So innumerable devices symbolised facts of Christian history, or aspects of Christian truth. In her ritual the Roman Catholic Church has given copious expression to religious symbolism. In architecture also symbolism appears in the cruciform shape of churches, in Orientation (q.v.), &c. In theological language it should also be noted that symbol sometimes means, like the Greek symbolon, a creed; hence symbolics is the study of the history and contents of Christian creeds.
On symbolism in art, see Mrs Jameson’s Sacred and Legendary Art, the last volume, by Husenbeth, of Baring-Gould’s Lives of the Saints (1872–92), Munter’s Sinnbilder (1825), Auber’s Symbolisme Religieux (1850), Tyrwhitt’s Art Teaching of the Primitive Church (1873), Miss Twining’s Symbols and Emblems (1885), Clement’s Christian Symbols (Boston, 1886), Miss Stokes’s translation of Didron’s Christian Iconography (1886), Allen’s Early Christian Symbolism in Great Britain and Ireland (1887), Hulme’s Symbolism in Christian Art (1891).