The Greek root pais (παῖς) and its counterpart paidos (παιδός), mean child. They are also the origin of the root paed/ped. Examples of its usage in current English include pediatric and pedobaptism.
Some other common Greek roots are anthrop (human), chron (time), dem (people), morph (form) and phon (sound).
The modern day Olympics has its foundation in the ancient Greek games. In honor of its heritage, during the closing ceremony and the parade of flags, the Greek flag is the first in the parade.