A posteriori

RHETORICAL QUESTION: See discussion under erotema.

RHOTACISM (from Greek, rho or "r"): A shift linguistically from [z] to an [r].

RHYME (from Old French, rime meaning "series," in turn adopted from Latin rithmus and Greek rhythmos): Also spelled rime, rhyme is a matching similarity of sounds in two or more words, especially when their accented vowels and all succeeding consonants are identical. For instance, the word-pairs listed here are all rhymes: skating/dating, emotion/demotion, fascinate/deracinate, and plain/stain. Rhyming is frequently more than mere decoration in poetry. It helps to establish stanzaic form by marking the ends of lines, it is an aid in memorization when performing oral formulaic literature, and it contributes to the sense of unity in a poem. The best rhymes delight because of the human fascination with varying patterned repetition, but a successful and unexpected rhyme can also surprise the reader (which is especially important in comic verse). They may also serve as a rhythmical device for intensifying meaning. Several different types of rhyme and rhyme schemes exist: see also cliché rhymes, crossed rhyme, double rhyme, end rhyme, exact rhyme, eye rhyme, feminine ending, half rhyme, head rhyme, imperfect rhyme, inexact rhyme, interlaced rhyme, internal rhyme, leonine verse, masculine ending, perfect rhyme, rhyme royal, slant rhyme, tail-rhyme, and triple rhyme.

RHYME ROYAL (Often spelled as "rime royal"): A seven-line stanzaic form invented by Chaucer in the fourteenth century and later modified by Spenser and other Renaissance poets. In rhyme royal, the stanzas are writen in iambic pentameter in a fixed rhyme scheme (ABABBCC). An example follows below from Wordsworth's Resolution and Independence:

There was roaring in the wind all night;
The rain came heavily and down in floods;
But now the sun is rising calm and bright.
The birds are singing in the distant woods;
Over his own sweet voice the stockdove broods;
The jay makes answer as the magpie chatters;
And the air is filled with pleasant noise of waters.

RHYME SCHEME: The pattern of rhyme. The traditional way to mark these patterns of rhyme is to assign a letter of the alphabet to each rhyming sound at the end of each line. For instance, here is the first stanza of James Shirley's poem "Of Death," from 1659. I have marked each line from the first stanza with an alphabetical letter at the end of each line to indicate rhyme:

The glories of our blood and state --------------A
Are shadows, not substantial things; -----------B
There is no armor against fate; ------------------A
Death lays his icy hand on kings: ---------------B
Scepter and crown -------------------------------C
Must tumble down, --------------------------------C
And in the dust be equal made ------------------D
With the poor crooked scythe and spade. -----D

Thus, the rhyme scheme for each stanza in the poem above is ABABCCDD. It is conventional in most poetic genres that every stanza follow the same rhyme scheme, though it is possible to have interlocking rhyme scheme such as terza rima. It is also common for poets to deliberately vary their rhyme scheme for artistic purposes--such as Philip Larkin's "Toads," in which the poetic speaker complains about his desire to stop working so hard, and his rhymes degenerate into half-rhymes or slant rhymes as an indication that he doesn't want to go to the effort of perfection. Among the most common rhyme schemes in English, we find heroic couplets (AA, BB, CC, DD, EE, FF, etc.) and quatrains (ABAB, CDCD, etc.), but the possible permutations are theoretically infinite.

RHYTHM (from Greek, "flowing"): The varying speed, loudness, pitch, elevation, intensity, and expressiveness of speech, especially poetry. In verse the rhythm is normally regular; in prose it may or may not be regular. See sprung rhythm for an exception to this general rule. Also see meter, dipody, and syzygy.

RIDDLE (from Old English roedel, from roedan meaning "to give council" or "to read"): A universal form of literature in which a puzzling question or a conundrum is presented to the reader. The reader is often challenged to solve this enigma, which requires ingenuity in discovering the hidden meaning. A riddle may involve puns, symbolism, synecdoche, personification (especially prosopopoeia), or unusual imagery.

For instance, a Norse riddle asks, "Tell me what I am. Thirty white horses round a red hill. First they champ. Then they stamp. Now they stand still." The answer is the speaker's teeth; these thirty white horses circle the "red hill" of the tongue; they champ and stamp while the riddler speaks, but stand still at the end of his riddle. Another famous example is the riddle of the sphinx from Sophocles' Oedipus Trilogy. The sphinx asks Oedipus, "What goes on four feet, on two feet, and then three. But the more feet it goes on, the weaker is he?" The answer is a human being, which crawls as an infant, walks erect on two feet as an adult, and totters on a staff (the third leg) in old age.

The earliest known English riddles are recorded in the Exeter Book, and they probably date back to the 8th century. Examples, however, can be found in Greek, Sanskrit, Hebrew, Arabic, Persian, and Chinese, and many other languages. Authors of Anglo-Latin riddles include Aldhelm of Sherborne, Archbishop Tatwine of Canterbury, and Abbot Eusebius of Wearmouth. A large Renaissance collection can also be found in Nicolas Reusner's Aenigmatographia (1602).