The mnemonic words of logic

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"In logic, a variety of syllogism depending on the quantity (universal or particular) and quality (affirmative or negative) of the propositions composing it. In the traditional logic the names of the moods (invented by Petrus Hispanus) are — First figure, Bārbără, Cēlārent, Dăriī, Fĕriō, Bărălipton, Cēlantēs, Dăbĭtīs, Fāpesmō, Frīsĕsŏmōrum; Second figure, Cēsărĕ, Cāmestres, Festīnŏ, Bărōcŏ; Third figure, Dāraptī, Fēlapton, Dĭsămis, Dātīsī Bōcardŏ, Fĕrīson. These names are merely mnemonic, and many of their letters are significant. The vowel a denotes a universal affirmative proposition, e the universal negative, i the particular affirmative, and o the particular negative. By the first syllable is indicated the major premise, by the second the minor, and by the third the conclusion. For example, the name Barbara shows that the first mood of the first figure consists of two universal affirmative premises leading to a universal affirmative conclusion. The same understanding is to be had in regard to the vowels of the other words. Certain of the consonants also are significant. Thus, all indirect moods designated by a word beginning with b should be reduced to Barbara, the first mood of the first figure; all that are designated by a word beginning with c, to the second mood, Celarent; all in d to Darii, the third; and all in f to Ferio, the fourth. Other letters indicate how to reduce indirect to direct moods: thus s signifies that the proposition denoted by the vowel immediately preceding is to be simply converted in the reduction: p, that the proposition denoted by the vowel immediately preceding should be converted per accidens; m, that the premises should be transposed — that is, the major should be made the minor, and conversely; and c, that the mood designated by the word in which it occurs should be reduced per impossibile...."

-- from the Century Dictionary definition for mood