Based on Greek and Roman principles, the rhythmic patterns of verse can be broken down into metrical feet, units of two or three syllables (taken to refer to the movement of the foot in beating time). Each foot represents a defined pattern of stressed (or long) and unstressed (or short) syllables.The four most common feet in English verse are the iamb (one short, one long - e.g. repeat), trochee (one long, one short - e.g. Peter), spondee (two long - e.g. pay day) and dactyl (one long, two short - e.g. possible).
