biped

a creature with two feet

centipede

a creature with 100 feet

impediment

something that stands in one's way; an obstacle

millipede

a creature with 1,000 feet

pedal

a lever that is moved with one's foot

peddler

a person who goes from door to door on foot trying to sell a product

pedestrian

a person who walks across the street on foot

pedicure

a foot treatment that could include soaking the feet and polishing the toenails

quadruped

a four-footed creature

tripod

a three-footed stand often used to balance a camera