Poetic form refers to the myriad rules of constructing a poem. Meter, rhythm, rhyme scheme and poetic structures are all elements of poetic form. Form is what distinguishes poetry from prose. Even free verse, which eschews poetic formalities, is written with poetic form. Poetic forms or structures result from combining several rules of poetic form.
Meter refers to the rhythmic pattern of a line or verse. Meter is made of a sequence of feet, or syllable types. Meter signifies how to stress each foot. In iambic pentameter, a meter common in Western poetry, every other syllable is stressed. The rhythm pattern is as follows: DUM-da-DUM-da-DUM. Other types of meter are trochaic, anapestic, dactylic, spondaic, pyrrhic and pyrrhic-spondee. Not all poetry follows set meter. Variations exist, but remain recognized poetic forms, such as substitution, elision, truncation and courtesy accent.
Lines and Stanzas
A line is a unit that dictates how a poem is divided, much like sentences and clauses in prose. A collection of lines is a stanza. Lines can be determined by rhythm or syllable count. Lines are composed of feet. A one-foot line is a monometer, two feet make a dimeter, and so on. Stanzas, built of lines, are also elements of poetic form. Two lines make a couplet and three make a triplet, which rhymes, or a tercet, which may or may not rhyme. Four lines is a quatrain, six is sestet and eight is an octave.
Rhyme and Rhyme Scheme
Rhyme refers to similar-sounding words, and rhyme scheme is the construction of a rhyming pattern. Rhyme is pleasant to the ear, but many poets eschew perfect rhymes. Other forms of rhyme are slant rhyme, alliteration, consonance, assonance and onomatopoeia. Limerick, couplet, rhyme royal, sonnet, Rondelet and triplet are just a few of the many examples of common rhyme schemes.
Poetic Forms and Kinds
All of these structures and more constitute various poetic forms. The form of a Shakespearian sonnet, also called Elizabethan or English sonnet, is constructed of eight lines of iambic pentameter followed by one iambic hexameter, and the rhyme scheme "abab bcbc c." Other poetic forms are blank verse, heroic couplet, ballad stanza, free verse, haiku, sestina and sonnet. Poetic kinds are distinct from poetic forms. They refer to tone and content. Elegy, satire and ode are all examples of poetic kinds.