An Allegory (from the Greek allos, other, and agoreuein, to speak), is a form of expression in which the words are symbolical of something. It is very closely allied to the metaphor, in fact is a continued metaphor.

Allegory, metaphor and simile have three points in common,—they are all founded on resemblance. "Ireland is like a thorn in the side of England;" this is simile. "Ireland is a thorn in the side of England;" this is metaphor. "Once a great giant sprang up out of the sea and lived on an island all by himself. On looking around he discovered a little girl on another small island near by. He thought the little girl could be useful to him in many ways so he determined to make her subservient to his will. He commanded her, but she refused to obey, then he resorted to very harsh measures with the little girl, but she still remained obstinate and obdurate. He continued to oppress her until finally she rebelled and became as a thorn in his side to prick him for his evil attitude towards her;" this is an allegory in which the giant plainly represents England and the little girl, Ireland; the implication is manifest though no mention is made of either country. Strange to say the most perfect allegory in the English language was written by an almost illiterate and ignorant man, and written too, in a dungeon cell. In the "Pilgrim's Progress," Bunyan, the itinerant tinker, has given us by far the best allegory ever penned. Another good one is "The Faerie Queen" by Edmund Spenser.