How do poetic feet help describe the meter of a line?

In poetry, a foot is the smallest metrical unit of measurement, consisting of a specific combination of stressed and unstressed syllables. Poetic feet help describe the metre of a line by establishing a recurring rhythmic pattern.12

The meter of a line is determined by two factors: the type of foot used and the number of times that foot appears in the line. For example, iambic pentameter is defined by the use of the iamb (an unstressed syllable followed by a stressed one) repeated five times.13

Common ways to describe the length of a line based on the number of feet include:
* Monometer: one foot
* Dimeter: two feet
* Trimeter: three feet
* Tetrameter: four feet
* Pentameter: five feet
* Hexameter: six feet1

Through the process of scansion, poets and readers identify these feet to reveal the underlying formal structure of the verse. While poets may use substitutions—replacing a standard foot with a different one—to create tension or variety, the identification of the prevailing feet remains the primary method for defining a poem's metrical design.12