1. ped (Latin)
Note: ped in Greek means child

2. biped a creature with two feet word meaning picture blenderartists.org
blenderartists.org 

3. centipede a creature with 100 feet word meaning picture
arthurevans.wordpress.com 
a creature with 100 feet
a-z-animals.com 

4. impediment Something that stands in the way; an obstacle word meaning
picture
impediment
images.yourdictionary.com 
Something that stands in the way; an obstacle

5. millipede a creature with 1,000 feet! word meaning picture
pestcemetery.com 
a creature with 1,000 feet!

6. pedal a lever that is moved with your foot word meaning picture
ux.stackexchange.com 
a lever that is moved with your foot
rapgenius.com 

7. word
meaning
picture
peddler
a person who goes from door to door on foot trying to sell a product
alleecreative.com 
thefrencheye.blogspot.com 

8. pedestrian a person who walks across the street on foot word meaning
picture
pedestrian
a person who walks across the street on foot

9. word
meaning
picture
pedicure
a foot treatment that could include soaking the feet and polishing the toenails

10. quadruped a four-footed creature word meaning picture
blog.oscarliang.net 
en.wikipedia.org 

11. tripod a three-footed stand often used to balance a camera word
meaning
picture
tripod
a three-footed stand often used to balance a camera
en.wikipedia.org 
fpvlab.com 

12. Remember: The Latin root word ped means foot.
The Greek root word ped means child.