From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( n.) A visible sign of an idea; an object, or the figure of an object, symbolizing and suggesting another object, or an idea, by natural aptness or by association; a figurative representation; a typical designation; a symbol; as, a balance is an emblem of justice; a scepter, the emblem of sovereignty or power; a circle, the emblem of eternity.

(2): ( n.) Inlay; inlaid or mosaic work; something ornamental inserted in a surface.

(3): ( n.) A picture accompanied with a motto, a set of verse, or the like, intended as a moral lesson or meditation.

(4): ( v. t.) To represent by an emblem; to symbolize.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]

"a device or figure employed to represent some moral notion. There are various opinions as to the lawfulness and expediency of emblems in religious matters, some considering it to be both allowable and useful thus to represent spiritual ideas to the bodily eye; others, again, holding it to be both presumptuous and dangerous, if not superstitious, to use any emblems of sacred things not warranted and enjoined by Scripture. This, at least, is certain, that it is quite as likely to lead to idolatry (answering to that of the Hindoos, Egyptians, etc.) as pictures or images giving a simple resemblance. The golden calf was meant for an emblem, but it was the occasion of gross idolatry."

Emblems are to be distinguished from symbols. Symbols are generally intended to represent revealed doctrines; emblems are "arbitrary representations of an idea of human invention" (Walcott). Thus a sword is the emblem of St. Paul. A lion, as indicating solitude, was chosen as the emblem of Jerome as a recluse. (See Idolatry);(See Image).