Glossary Term of the Day:

A pentameter is a line made up of five feet. A foot -- the basic unit of measurement of accentual-syllabic meter -- usually contains one stressed syllable and at least one unstressed syllable...

• Iambic Pentameter:
  The word "iambic" describes the type of foot that is used. In English, the rhythm is created through the use of stress, alternating between unstressed and stressed syllables. The English word "trapeze" is an example of an iambic pair of syllables, since the word is made up of two syllables and is pronounced with the stress on the second syllable ("tra—PEZE", rather than "TRA—peze"). Iambic pentameter is a line made up of five such pairs of short/long, or unstressed/stressed, syllables, as seen in the excerpt below:
  
  
  excerpt from "The Waking" by Theodore Roethke

  I wake to sleep, and take my waking slow.
  I feel my fate in what I cannot fear.
  I learn by going where I have to go.
  
  We think by feeling. What is there to know?
  I hear my being dance from ear to ear.
  I wake to sleep, and take my waking slow.
  
  Of those so close beside me, which are you?
  God bless the Ground! I shall walk softly there,
  And learn by going where I have to go....
  
  
  
• Dactylic Pentameter:
  The dactyl is made of a stressed syllable followed by two unstressed syllables. The words “poetry” and “basketball” are both dactylic. Alfred Lord Tennyson's poem "The Charge of the LIght Brigade" is written in dactylic meter:
  
  
  excerpt from "The Charge of the Light Brigade" by Alfred Lord Tennyson

  I
  Half a league, half a league,
  Half a league onward,
  All in the valley of Death
  Rode the six hundred.
  “Forward, the Light Brigade!
  Charge for the guns!” he said.
  Into the valley of Death
  Rode the six hundred.
  
  II
  “Forward, the Light Brigade!”
  Was there a man dismayed?
  Not though the soldier knew
  Someone had blundered.
  Theirs not to make reply,
  Theirs not to reason why,
  Theirs but to do and die.
  Into the valley of Death
  Rode the six hundred....

The pentameter is the most common metrical line in English. See also Blank Verse.