2. Metaphor is the assumption of a transfer of meaning in some word, as when we say segetes fluctuare (the grain-fields billow), vites gemmare, when we do not find any waves or gems in these things, but the words are transferred from the old application to a new one. These and other tropical forms of speech are veiled with figurative cloaks with reference to the things to be understood, with the view that they may exercise the intelligence of the reader, and may not be cheap because they are unadorned and easily apprehended.
22. Allegory is the saying of things that do not belong to the matter in hand (alienoloquium), for one thing is said, another is understood; as, tres in littore cervos conspicit errantes, where the three leaders of the Punic war, or the three Punic wars are indicated; and in the Bucolics, aurea mala decem misi, i.e., ten pastoral eclogues to Augustus. There are many species of this figure, of which seven are conspicuous: irony, antiphrasis, enigma, charientismus, paroemia, sarcasmus, astysmus.
23. It is irony where the thought is given a contrary meaning by the manner of speech. By this figure something is said cleverly, either in the way of accusation or insult, as the following:
Vestras, Eure, domos, illa se jactet in aula
Aeolus, et clauso ventorum carcere regnet.
And why aula (palace) if it is carcer (prison)! It is made clear by the manner of speech, for the manner of speech says carcer. Jactet in aula is irony, and the whole is expressed in a contradictory manner of speech by the figure of irony which mocks by praising.
24. Antiphrasis is language to be understood to the contrary, as, lucus (sacred grove), since it is without light (lux) because of the excessive gloom of the woods....
25. Between irony and antiphrasis there is this difference, that irony indicates by the manner of speaking alone what is meant, as when we say to a man doing ill, “Bonum est quod facis”. But antiphrasis indicates the contrary not by the voice of the speaker, but only in the words, whose derivation is the opposite [of their meaning].
Chapter 39. On metres.
4. Whatever is measured by verse feet is a poem (carmen). It is thought that the name was given because it was pronounced rhythmically (carptim), or ... because they who sang such things were supposed to be out of their minds (mente carere).