A prosodic foot is a unit of rhythm in poetry, consisting of two or more syllables. The two most common types of prosodic feet are the DACTYL (6 letters) and the IAMB (4 letters). A DACTYL is a three-syllable foot with the stress on the first syllable, while an IAMB is a two-syllable foot with the stress on the second syllable. Prosodic feet are used to create a regular pattern of stressed and unstressed syllables in a poem, which can help to create a sense of rhythm and meter.