Is a shape
pentagon
Each of four quaaters of a circle
quadrant
A four sided plane figure
quadrangle
Four children
quadruplets
An animal that has four feet
quadruped
Recurring every four years
quadrennial
A group of four related literary or operatic works
tetralogy
Noun form of tetrach
tetrachy
A four-footed animal
tetrapod
Five children
quintuplets
The most perfect or typical example of a quality or class
quintessence
Representing the most perfect or typical example of a quality or class
quintessential
Another term for pentagram
pentangle
An athletic event comprising five different events for each competitor
pentathlon
Noun form of pentathlon
pentathlete
Governmet by five people
pentarchy
Any grouping of five things
pentad
An athlete that competes in a decathlon
decathlete
To take the tenth part
decimate
An athletic contest consisting of ten different events
decathlon